GM Service Manual Online
For 1990-2009 cars only

Engine Speed: Display shows crankshaft rotation speed in revolutions per minute (RPM) from 0 to 16384.

Desired Idle Speed: Display shows the idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the engine at the desired idle speed from 0 to 2040 RPM.

MAF: Display shows the amount of airflow entering the engine in grams per second (g/s) from 0 to 655. The scan tool will display 0 gms/sec only until 4X reference pulses are received ,cranking or running. The PCM updates the MAF sensor display only after 4X reference pulses have been received during an ignition cycle. If during an ignition cycle the vehicle were to stall the MAF display would indicate the last airflow reading obtained while 4X reference pulses were present. If no airflow is monitered by the PCM while the vehicle is running the MAF display will default to 1.2 grams per second.

TP Sensor: Display shows the amount of throttle opening in volts, with closed throttle near 0 volts and wide open throttle above 4.0 volts.

ECT: Display shows the temperature of the engine coolant from -40° to 215°C and -40° to 419°F

IAT: Display shows the temperature of the intake manifold air from -40° to 215°C and -40° to 419°F

MAP: Display shows manifold pressure in Kilo Pascals (Kpa) from 10 to 105. At key ON ,engine not running, the MAP value will reflect barometric pressure.To check for an accurate MAP reading multiply your local barometric pressure by 3.386 to obtain a map value that should be within 2 Kpa of displayed value at key ON ,engine not running.

BARO: Display shows the BARO in Kpa from 11 to 105. the BARO reading is taken at key ON and is corrected at wide open throttle (WOT). Multiply your local barometric pressure by 3.386 to obtain a BARO value that should be within 2 Kpa of the displayed value.

TP Normalized: Display shows percent and degrees from 0 to 100 percent and 0.0 to 81.6 degrees. The PCM will compensate for deposits in the throttle body by learning the closed throttle position as zero percent and zero degrees.

Engine Load: Display shows engine load in percent from 0 to 100. Engine load is calculated by the PCM by engine speed and mass airflow. Reading should increase with an increase in RPM and airflow.

IAC Position: Display shows the commanded IAC pintle position in counts from 0 to 1024. The higher the number of counts, the greater the commanded idle speed. zero is the fully seated position. Idle air control should respond fairly quickly to changes in engine load to maintain desired idle RPM.

Injector. PWM Bank 1: Display shows injector pulse width for cylinders 1, 3, 5, 7 in milliseconds (ms) from 0 to 99.6.

HO2S Bank 1 Sensor 1: Display shows bank 1 sensor 1 HO2S voltage from 0 to 1.16.

Injector. PWM Bank 2: Display shows injector pulse width for cylinders 2, 4, 6, 8 in milliseconds (ms) from 0 to 99.6.

HO2S Bank 2 Sensor 1: Display shows bank 2 sensor 1 HO2S voltage from 0 to 1.16.

R/L Status Bank 1 Sen 1: Display shows HO2S bank 1 sensor 1 RICH or LEAN which indicates whether oxygen sensor voltage is above, rich, or below, lean, bias voltage. Display should change constantly, indicating that the PCM is controlling bank 1 air/fuel mixture.

R/L Status Bank 2 Sen 1: Display shows HO2S bank 2 sensor 1 RICH or LEAN which indicates whether oxygen sensor voltage is above, rich, or below, lean, bias voltage. Display should change constantly, indicating that the PCM is controlling bank 2 air/fuel mixture.

HO2S Bn 1 Sen. 2: Display shows bank 1 sensor 2 HO2S voltage from 0 to 1.16.

HO2S Bank 1 Sensor 3: Display shows bank 1 sensor 3 HO2S voltage from 0 to 1.16.

Rich to Lean Status Bn 1 Sen 2:Display shows Rich or Lean. This represents the first HO2S in the catalyst monitor. Display should change constantly while in closed loop.

R/L Status Bank 1 Sen 3: Display shows Rich or Lean. This represents the POST HO2S in the catalyst monitor (located downstream of the catalyst). Display should change much slower when compared to the Bank 1 and Bank 2 fuel control sensors indicating the catalyst is operating efficiently.

Fuel Trim Cell: Display Shows Fuel Trim Cell range from 0 to 16. Fuel trim cell is dependent upon engine speed and mass air flow readings. A plot of RPM vs. MAF is broken into 16 cells. Fuel trim cell indicates which cell is currently active.

Fuel Trim Learn: Display shows Disabled or Enabled. When conditions are appropriate for enabling long term fuel trim corrections, Fuel Trim Learn will display Enabled. This indicates that the long term fuel trim is responding to the short term fuel trim. If the display shows Disabled then long term fuel trim will not respond to changes in short term fuel trim.

Short Term FT Bank 1: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the short term fuel trim is 128 counts or 0%. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the bank 1 (rear) HO2S. A count less than 128 or less than 0% indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the bank 1 (rear) HO2S.

Long Term FT Bank 1: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the long term fuel trim is 128 counts or 0%. The long term fuel trim is based on short term fuel trim learned values. It is stored in memory blocks of the long term memory according to MAP and RPM values. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine. A count less than 128 or a percentage less than 0% indicates time is being subtracted from the injector pulse width, reducing the amount fuel to the engine.

Short Term FT Bank 2: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the short term fuel trim is 128 counts or 0%. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the bank 1 (rear) HO2S. A count less than 128 or less than 0% indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the bank 2 (front) HO2S.

Long Term FT Bn 2: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the long term fuel trim is 128 counts or 0%. The long term fuel trim is based on short term fuel trim learned values. It is stored in memory blocks of the long term memory according to MAP and RPM values. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine. A count less than 128 or a percentage less than 0% indicates time is being subtracted from the injector pulse width, reducing the amount fuel to the engine.

Loop Status: Display shows OPEN LOOP or CLOSED LOOP. Closed Loop displayed indicates that the PCM is controlling fuel delivery according to oxygen sensor voltage. In Open Loop, the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on other input sensors. Closed Loop operation should begin when the oxygen sensor becomes active, engine coolant temperature exceeds 5°C (41°F) for more than 30 seconds and the PCM has seen a RPM of 1200 or greater for 10 seconds. At extremely high ambient temperatures or when towing a trailer, it is possible for the system to remain in Open Loop operation to control catalytic converter temperatures.

Engine Run Time: Display shows Hours: minutes: seconds. Engine run time measures how long the engine has been running. When the engine is turned OFF, the timer is reset to zero.

MIL: Display shows ON or OFF. The MIL (Service Engine Soon) is controlled by the PCM and is used to indicate that the PCM has detected a problem that affects vehicle emissions, driveabillity or could cause powertrain damage.

Ignition 1: Display shows voltage from 0 to 25.5. This represents the system voltage measured by the PCM at its ignition feed.

High Elec Load: Display shows Yes or No. Display should show Yes if several accessories are in operation.

Generator PWM: Display shows Generator F Terminal duty cycle in percent from 0 to 100. The generator is able to produce the desired voltage by varying the duty cycle of the field current. At low engine speeds, the field may have a duty cycle of 90 percent. At higher engine speeds, and lower electrical loads, the duty cycle will be less. The generator produces a PWM signal that is monitored by the PCM.

FP Relay: Display shows Fuel Pump Relay as ON or OFF. When the ignition switch is turned to the ON position, the PCM turns the fuel pump relay ON for two seconds. If the PCM does not receive ignition reference pulses within two seconds, the PCM will shut OFF the fuel pump.

FP Voltage Feedback: Display shows feedback of 0 to 25.5 volts. FP volt feedback provides information to the PCM about the fuel pump power supply condition through the fuel pump circuit.

Cam Pulse: Display shows counts from 0 to 255. This parameter is the number of cam signal inputs to the PCM. The counter will reset after 255 counts are reached.

IC Mode: Display shows PCM or ICM. In PCM mode, the PCM controls the ignition timing. The PCM calculates the desired ignition timing based on information the PCM receives from the input sensors. In Ignition Control Module (ICM) mode, the ignition system operates independently from the PCM. The Ignition Control Module maintains a base ignition timing of 10 degrees BTDC and is able to change this ignition timing slightly with increased engine speed. Ignition control mode is in affect whenever an ignition control fault is detected while the engine is running and it will have a noticeable effect on driveability.

Spark: Display shows spark advance in degrees from -90 to 90. A negative number indicates degrees of retard. This is a display of the spark advance calculation which the PCM is programming into the ignition system. The PCM computes the desired spark advance using data such as Engine Temperature, RPM, Engine Load, Vehicle Speed and Operating Mode.

Knock Retard: Display shows knock retard from 0 to 45 degrees. Which indicates the amount of spark advance in degrees that the PCM is removing from the Ignition Control (IC) in response to the Knock Sensor (KS) signal.

KS Active Counter: Display is shown in counts from 0 to 255. Display shows the number of instances of engine detonation detected by the knock sensor in one-eighth of a second from 1 to 255.

Vehicle Speed: Display shows vehicle speed in mph and km/h from 0 to 159 mph (0 to 255 km/h). The vehicle speed is converted into mph and km/h for display.

Throttle at Idle: Display shows No or Yes. This display indicates whether the TP Angle being monitored by the PCM is at 0 percent when the throttle is closed.

PNP: Display shows P-N---- or -R-OD21. P-N---- displayed indicates the gear select lever is in Park or Neutral. -R-OD21 displayed indicates the gear select lever is in Reverse, Drive, or Low Range.

PSP Switch: Display shows Normal or Hi Press. The PCM compensates engine idle depending on steering load condition. Scan tool will display Hi Press. due to increase of power steering fluid pressure while turning the steering wheel. Scan tool displays Normal under no load condition.

TCC Brake Switch: Display shows Released or Applied. This parameter indicates the state of the TCC brake switch circuit input. Released indicates a B+ voltage input ,brake switch closed - brake pedal released. Applied indicates a 0 voltage input brake switch open - brake pedal applied.

Extended Travel Brake: Display shows Released or Applied. This parameter indicates the state of the extended travel brake switch contacts of the torque management brake switch. Scan tool will display Released with the brake pedal released and Applied with the brake pedal applied approximately 40%.

TCC Slip Speed: Display shows TCC Slip Speed in RPM from -4096 to 4064. Display shows the amount of slip between the engine and transaxle input shaft.

Commanded EGR: Display shows commanded EGR position in percent from 0 to 100. Commanded EGR is the EGR pintle position which is being commanded by the PCM which should be very close to the Actual EGR Pos. display.

Actual EGR Pos: Display shows EGR position in percent from 0 to 100. Actual EGR position represents the linear EGR pintle position signal in percent of travel. 0% displayed indicates a closed EGR valve, EGR flow not allowed.

EGR Closed Pintle Pos.: Display shows position in volts from 0.0 to 5.00. This display represents the voltage that the PCM has learned as the fully closed EGR valve, 0% pintle position.

EGR Pintle Position: The EGR valve contains a potentiometer type position sensor that provides a voltage proportional to the pintle position . Pintle position is used by the PCM for Closed Loop control of valve pintle position to follow commanded position for diagnostics, and to correct fuel and spark for EGR. This display indicates the actual position of the EGR pintle sensor.

Ignition 0: Displays voltage from 0 to 25.5. This represents the system voltage measured by the PCM at its Ignition 0 feed.

ECT at Start Up: Displays start up ECT in °C/°F. This display is the ECT when engine start up occurred.

TP Angle: Display shows throttle angle in percent. Display is computed by the PCM from TP Sensor voltage. Display should read 0% at idle, 100% at wide open throttle (WOT).

EVAP Vacuum Sw: Display shows No Flow or Purging. The EVAP purge vacuum switch is a normally closed switch positioned in the purge line between the canister and the EVAP purge solenoid. The EVAP purge vacuum switch will open when vacuum increases to greater than five inches of water in the purge line. The EVAP purge vacuum switch is used by the PCM to monitor EVAP canister purge solenoid operation and purge system integrity. The EVAP purge vacuum switch should be closed to ground with no vacuum present, 0% EVAP purge solenoid PWM. With EVAP purge solenoid PWM at 25% or greater the EVAP purge vacuum switch should open and purge should be indicated.

EVAP Canister Purge: Display shows EVAP Purge solenoid in percent from 0 to 100. The evaporative emission purge valve solenoid is a proportional signal used to control the evaporative emission canister purge function. 0% means the valve is commanded fully closed while 100% means that the valve is commanded fully open.

Air Fuel Ratio: Display shows Air Fuel Ratio from 0 to 1 to 25.5 to 1. Display indicates the air fuel ratio based on oxygen sensor inputs. The PCM uses fuel trims to adjust fueling to attempt to maintain an air fuel ratio of 14.7 to 1.

Power Enrichment: Display shows Inactive or Active. The scan tool indicates when Power Enrichment mode is active, moderate to heavy acceleration.

Traction Control: Display shows Inactive or Active. Display will show Active if the PCM receives a signal from the Electronic Brake and Traction Control Module, EBTCM, requesting torque reduction during a traction control maneuver.

Desired Torque ABS/TCS: Display shows Desired Torque Level in percent from 0 to 100. The EBTCM sends a Desired Torque Level signal request to the PCM to decrease torque output from the powertrain to reduce wheel slip during acceleration for traction control.

Non-Driven Wheel Speed: Display shows MPH / km/h from 0 to 158 MPH, 0 to 255 km/h. This display is the non-drive (rear) wheel speed sent to the EBTCM, used for traction control and Anti-Lock braking and is monitored by the PCM.

Traction Control Torque: Display shows percent from 0 to 100. This is the calculated torque output from the engine to the transaxle used by the EBTCM for traction control system operation.

Service Spark Retard: Display shows degrees from 0 to 4. This displays the amount of spark retard in degrees from the base spark timing of 10 degrees before top dead center. Service Spark Retard is used to compensate for poor fuel quality or low octane fuel. It can only be adjusted with a scan tool. If the battery is disconnected the service spark retard setting will reset to zero.

Ref. Volts Low: Display shows Ignition Ground Voltage in volts. The PCM keeps the voltage difference between ignition ground and PCM ground shifted by approximately 2.5 volts. The scan tool rescales the 2.5 volts to indicate 0 volts on the display. A circuit reading of 2.500 volts means the ignition and the PCM grounds are at the same level which would be displayed as 0 volts on the scan tool. A circuit reading of 1.000 volt means the ignition ground voltage is 1.5 volts lower than the PCM ground. A circuit reading of 3.500 volts means the ignition ground voltage is 1.0 volt above the PCM ground.

4X Ref. Pulse Counter: Display shows counts from 0 to 255. This is the number of 4X reference pulses between cam pulses. The normal amount of pulses should be 8 with engine running.

Ign. Cycle Cnter: Display shows counts from 0 to 50. The counts increase by one with each On to Off key cycle. When a DTC sets, the counter is set to zero. If the DTC becomes history, the counter will increment with each key cycle until another DTC is set, or until the key has been cycled at which time the DTC will be erased.

A/C Relay: Display shows A/C relay On or Off. This display represents the commanded state of the A/C Clutch Control Relay. Clutch should be engaged when On is displayed.

FC Relay 1: Display shows Fan Control Relay state as On or Off. When the PCM is commanding the Fan 1 Relay On, the scan tool display will switch from Off to On.

FC Relay 2 and 3: Display shows Fan Control Relay state as On or Off. When the PCM is commanding the Fan 2 and 3 Relays On, the scan tool display will switch from Off to On.

Outside Air Temp: Display showsn -40°C (-40°F) to 102°C (215°F).This is the outside temperature sent from the HVAC to the PCM across the data link.

Engine Oil Level: Display shows Oil Level OK or Low. The PCM monitors the engine Oil Level during a cold key ON and if the Oil Level switch indicates approximately two quarts below full a message is sent indicating oil is Low. In 1996 model year vehicles this display will indicate what the oil level was indicated at the last cold key ON. In later model year vehicles this display indicates the actual state of the Oil Level circuit/switch.

Engine Oil Life: Display shows Engine Oil Life in percent from 0 to 100. This display represents the Engine Oil Life Index that is calculated and maintained by the PCM.

Trans. Fluid Temp: Display shows -40°C (-40°F) to 215°C (419°F).This is the Transaxle fluid temperature in degrees.

Trans. Oil Life: Display shows Transaxle Oil Life in percent from 0 to 100. This display represents the Transaxle Oil Life Index that is calculated and maintained by the PCM.

Shift Sol. Valve 1: Display shows shift solenoid 1 as On or Off. When the automatic transaxle is in first or fourth gear, the scan tool should display On. When the transaxle is in second or third gear, the scan tool should display Off.

Shift Sol. Valve 2: Display shows shift solenoid 2 as On or Off. When the automatic transaxle is in first or second gear, the scan tool should display On. When the transaxle is in third or fourth gear, the scan tool should display Off.

Current Gear: Display shows Current Gear as 1, 2, 3 or 4. This display is the decoded value converted to 1, 2, 3 or 4 from the state of the solenoids, PCM commanded.

Trans. Range or TFP Switch: Display shows Drive 1, Drive 2, Drive 3, Drive 4, Reverse, P/N, or Invalid. This is the decoded manual valve position from the transaxle range pressure switch.

Trans Range A/B/C or TFP Switch A/B/C: Display shows ON/OFF or High or Low. This shows the state of the three outputs from the transaxle range pressure switch which is used to indicate the actual manual valve position. ON or High = open circuit, OFF or Low = grounded circuit.

TCC Enable: Display shows TCC as Disabled or Enabled. This display is the allowed state of the Torque Converter Clutch.

TCC Duty Cycle: Display shows TCC Duty Cycle in percent from 0 to 100. This parameter is the commanded percent of ON time of the TCC solenoid. 100% represents an On, energized, commanded state. 0% represents a Off, non-energized, commanded state.

Engine Oil Pres: Display shows OK or Low. Display will show OK if the Oil Pressure is above 4.5 PSI.

Brake Boost. Vac: Display shows Brake Booster Vacuum in kilopascles and voltage from -10 to 84 kPa, 0.00 to 5.00 volts. This display is the signal from the Brake Booster Vacuum Sensor attached to the vacuum booster assembly

Sel. Lever Sw or Transmission Range: Display shows Invalid, Drive 4, Drive 3, Reverse, P/N, Drive 1, Drive 2. This display is the decoded transaxle range, from the 4 PRNDL inputs.

Sel Level Sw A/B/C/P or Trans Range A/B/C/P: Display shows ON/OFF or High or Low for each of the four PRNDL inputs. ON or High = open circuit, OFF or Low = grounded circuit.

MIL Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output #1 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

PCM Ride Control Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) B output #1 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

PCM Ride Control: Display shows Normal or Firm. This parameter is the operating mode that the ride control is operating at, for vehicle stability.

Vehicle Speed Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output #2 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

Tachometer Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output # 3 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

Delivered Torque Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output #4 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

EVAP Purge Solenoid Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output #5 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

A/C Relay Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) B #3 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

Cruise Requested: Display shows No or Yes. The display represents the state of the cruise request input from the Stepper Motor Cruise Control (SMCC) module.

Cruise: Display shows cruise state as Disabled or Enabled. If the PCM detects conditions that the vehicle is operating under that cruise should not be allowed, i.e. low vehicle speed, it will send out a signal to disable cruise. If cruise will be allowed it will send out a signal to enable cruise.

Cruise Enable Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) B #4 for an open or shorted condition if one of the conditions exists the fault line will go Low. The scan tool will display the condition that is present.

Shift Sol. 1 Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) #2 output #5 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

Shift Sol. 2 Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) #2 output #6 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

TCC Solenoid Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) #2 output #7 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.

Driver 1 Ground: Display shows OK, Over Voltage, Over Current. This displays the state of ODM #1's input circuit.

Driver 2 Ground: Display shows OK, Over Voltage, Over Current. This displays the state of ODM #2's input circuit.

Driver 1: Display shows OK or Fault. This displays the state of QDM #1 output circuits with fault being open or grounded. The output circuits that are monitored are the components connected to PCM connector C2 terminals 30,31,32 and 33. Not all terminals may be used depending upon vehicle make and model.

Injector 1 thru 8: Fault Display shows OK or Fault. Scan tool will display fault if the PCM has detected an improper voltage level in any of the fuel injectors circuits to determine if any of the eight injectors are misfiring.

VTD Fuel Cont: Display shows No or Yes. The Vehicle Theft Deterrent (VTD) controller will not disable fuel on initial start-up. The VTD must receive the correct message from the ignition lock assembly before reaching the fuel continue/disable point. If the correct message is not received, fuel injection will be disabled for 10 minutes.

IPC Fuel Disabled: Display shows Inactive or Active. The IPC will send out a fuel disable message to the PCM if the incorrect message from the ignition lock assembly has been received.

VTD Password: Display shows OK or Incorrect. The PCM will store a learned password that it receives from the vehicle theft deterrent (VTD) module. The display will show if the password that was sent was the correct password.

Auto Learn Timer: Display shows Inactive or Active. The auto learn timer is the indication if the Vehicle Theft Deterrent (VTD) is in learn mode and has not timed out.

VTD Password Learn Mode: Display shows Inactive or Active. The learn mode must be active for the PCM to learn the correct password from the Vehicle Theft Deterrent (VTD) system. This allows learning for the replacement of the PCM.

Odometer: Display shows miles from 0 to 1677722. This display is the actual vehicle miles stored in the PCM.

CL Fuel Control Sw. Point O2S: Display shows millivolts from 0 to 1107. This is the oxygen sensor voltage at which closed loop is achieved.

HO2S Warm Up Bn 1 Sen. 1: Display shows minutes and seconds from 0:00 to 4:15. This parameter is how much time it takes for the oxygen sensor to start its voltage swings over the rich/lean threshold.

HO2S Warm Up Bn 2 Sen. 1: Display shows minutes and seconds from 0:00 to 4:15. This parameter is how much time it takes for the oxygen sensor to start its voltage swings over the rich/lean threshold.

HO2S X Counts Bank 1: Display shows counts from 0 to 255. This display is the number of times the oxygen sensor voltage crosses over the rich/lean threshold during a one second interval.

HO2S X Counts Bank 2: Display shows counts from 0 to 255. This display is the number of times the oxygen sensor voltage crosses over the rich/lean threshold during a one second interval.

L/R Transition Time Bn 1 Sen. 1: Display shows time in milliseconds from 0.0 to 3187.5 ms. Display is the time for the HO2S voltage to change from the lean threshold to the rich threshold.

R/L Transition Bn 1 Sen. 1: Display shows time in milliseconds from 0.0 to 3187.5 ms. Display is the time for the HO2S voltage to change from the rich threshold to the lean threshold.

L/R Transition Bn 2 Sen. 1: Display shows time in milliseconds from 0.0 to 3187.5 ms. Display is the time for the HO2S voltage to change from the lean threshold to the rich threshold.

HO2S Rich/ Lean Transition Time Bn 2 Sen. 1: Display shows time in milliseconds from 0.0 to 3187.5 ms. Display is the time for the HO2S voltage to change from the rich threshold to the lean threshold.

HO2S Lean/ Rich Transition Time Bn 1 Sen. 2: Display shows time in milliseconds from 0.0 to 3187.5 ms. Display is the time for the HO2S voltage to change from the lean threshold to the rich threshold.

HO2S Rich/ Lean Transition Time Bn 1 Sen. 2: Display shows time in milliseconds from 0.0 to 3187.5 ms. Display is the time for the HO2S voltage to change from the rich threshold to the lean threshold.

Calc. Converter Temp: Display shows temperature in degrees C and degrees F from 0°C (32°F) to 765°C (1409°F). This parameter is the PCM calculated temperature of the Three Way Catalyst.

L/R Switch Bank 1 Sen. 1: Display shows counts from 0 to 65535. This displays the number of counts when the HO2S voltage swings above the rich mean threshold.

R/L Switch Bank 1 Sen. 1: Display shows counts from 0 to 65535. This displays the number of counts when the HO2S voltage swings below the lean mean threshold.

L/R Switch Bank 2 Sen. 1: Display shows counts from 0 to 65535. This displays the number of counts when the HO2S voltage swings above the rich mean threshold.

Rich/Lean Switch Bn 2 Sen. 1: Display shows counts from 0 to 65535. This displays the number of counts when the HO2S voltage swings below the lean mean threshold.

Lean/Rich Switch Bn 1 Sen. 2: Display shows counts from 0 to 65535. This displays the number of counts when the HO2S voltage swings above the rich mean threshold.

Rich/Lean Switch Bn 1 Sen. 2: Display shows counts from 0 to 65535. This displays the number of counts when the HO2S voltage swings below the lean mean threshold.

Misfire History #1 (thru) #8: Display shows counts from 0 to 65535. The Misfire History counters display the total level of misfire that has been detected on each cylinder. The Misfire History counters will not update or show any activity until a misfire, DTC P0300, has become active. The Misfire History counters will update every 200 cylinder firing events.

Total Misfire Passes Since First Fail: Display shows counts from 0 to 65535. The Misfire Passes counter shows the relative number of passed misfire tests since P0300 went active.

Total Misfire Failures Since First Fail: Display shows counts from 0 to 65535. The Misfire Failure counter shows the relative number of failed misfire tests since P0300 went active.

Cycles of Misfire Data: Display shows counts from 0 to 100. Displays which engine cycle of the 100 engine cycle test the PCM is collecting data for P0300.

Misfire Cycle Delay Counter: Display shows counts from 0 to 255. If the misfire test is interrupted, due to the vehicle coming outside the test conditions for P0300, this display will show the number of engine cycles left before the test is re-enabled and data collection will resume.

Revs. w/Misfire: Display shows counts from 0 to 200. The counts displayed are the number of misfires counts detected in the last misfire test. A misfire count is two times the number of misfires

Msf. Rev. Status: Display shows Accepted or Rejected. Accepted means the misfires are valid misfires. Rejected means the misfires were not actual misfires but an indication rough road.

Total Misfire: Display shows counts from 0 to 255. This display indicates the total number of cylinder firing events that were detected as being misfires during the last 200 crankshaft revolution sample period.

Misfiring Cyl: Display shows Primary Cyl. 1-8 and Secondary Cyl. 1-8. If a misfire is present this display will show the primary missing cylinder and if more than one, the secondary missing cylinder. If no misfire is present the display will not show a number.

Misfire Current #1 (thru) #8: Display shows Misfire Current counters increment at a rate according to the number of possible misfires being detected on each cylinder during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all the cylinders.

Engine Speed at Misfire: Display shows RPM at which DTC P0300 was set. When a misfire is detected, the PCM will store the RPM at which the misfire occurred.

Load at Misfire: Display shows load in percent at which DTC P0300 was set. When a misfire is detected, the PCM will store the percent of load at which the misfire occurred.

ECT at Misfire: Display shows ECT in degrees at which DTC P0300 was set. When a misfire is detected, the PCM will store the ECT in degrees at which the misfire occurred.