GM Service Manual Online
For 1990-2009 cars only
Accelerator Pedal Position Indicated Angle: This parameter displays the angle of the accelerator pedal position (APP) as calculated by the control module using the signals from the APP sensors. The APP indicated angle is a range of values indicating a low percentage when accelerator pedal is not depressed to a high percentage when the accelerator pedal is fully depressed.

Battery Voltage Signal: The scan tool displays 0-20 Volts. The scan tool displays the voltage as received by the module or the 72-08 battery voltage message from the DIM/IPM over class 2 lines.

Brake Pedal Position Circuit Signal: This parameter displays the circuit status of brake pedal position (BPP) determined by the brake pedal circuit. this scan tool will display Applied when the brake pedal is depressed, and Released when the brake pedal is not depressed.

Brake Pedal Position Signal: This parameter displays the switch status of brake pedal position (BPP) determined by brake pedal switch. The scan tool will display Applied when the brake pedal is depressed, and Released when the brake pedal is not depressed.

Brake Pedal Signal Status: This parameter displays the serial data message of the brake signal from the electronic brake and traction control module (EBTCM).

Clutch Start Switch (if equipped): This parameter displays the clutch pedal status from the clutch start switch determined by the control module.

Crank Request Signal: The scan tool displays Yes/No. The scan tool displays No until the ignition is placed into the START position then Yes is displayed.

EC Ignition Relay Circuit Status: This parameter displays the state of the engine control (EC) ignition relay control circuit output driver. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground or a short to voltage on the circuit.

EC Ignition Relay Command: This parameter displays the commanded state of the EC ignition relay control circuit. The scan tool will display ON or OFF. ON indicates the EC ignition relay control circuit is being grounded by the control module, allowing voltage to the ignition system. OFF indicates the EC ignition relay is not being commanded on by the control module.

EC Ignition Relay Feedback Signal: This parameter displays the voltage signal was sent to the control module from the EC ignition relay. The scan tool will display battery voltage when the engine is running. The scan tool will display no voltage when the relay is OFF.

ECT Sensor: This parameter displays the engine coolant temperature based on the input from the engine coolant temperature sensor. When the coolant temperature is low, the scan tool will display a low temperature. When the coolant temperature is high, the scan tool will display a high temperature.

Engine Oil Pressure Sensor: This parameter displays the engine oil pressure as calculated by the control module based on the engine oil pressure (EOP) sensor signal. The scan tool displays the oil pressure with the engine running. The engine oil pressure sensor has a range of values indicating a low value when the oil pressure is low and a high value when the oil pressure is high.

Engine Speed: This parameter displays the crankshaft rotation speed as calculated by the control module based on an input from the crankshaft position (CKP) sensor. The scan tool will display a high value at high engine speed and a low value at low engine speed.

GEN F-Terminal Signal: The scan tool displays 0-100%. The scan tool displays 0-10% until the engine is started and the EMC receives a signal from the generator then OK is displayed.

GEN L-Terminal Circuit Status: This parameter indicates the status of generator L - terminal circuit output driver. The scan tool will display OK, incomplete, Open, Short B+, or Short Gnd. OK indicates that no circuit faults are detected during the current test. Incomplete indicates the circuit test is not complete. Others indicate that a short or open circuit/component exists, electronically disconnecting the circuit/component form the control module.

GEN L-Terminal Signal Command: This parameter indicates the status of GEN L-Terminal Signal Command. If generator is activated, the scan tool displays high values. If it is inactivated, it displays low values.

Ignition 0 signal: The scan tool displays On/Off. The scan tool displays On when the voltage is present at the ignition 0 voltage circuit of the ECM.

Ignition 1 Signal: The scan tool displays 0-20 Volts. The scan tool displays the voltage as received on the Ignition 1 circuit to the ECM.

Ignition 1 Signal: This parameter displays On when the control module detects a voltage signal at the ignition 1 input terminal.

Ignition Accessory Signal: This parameter displays the state of the ignition accessory input to the control module from the ignition switch. The scan tool will display On when the ignition switch is in the ignition accessory position. The scan tool will display Off when the ignition switch is in any other position.

Initial Brake Apply Signal: The scan tool displays Applied/Released. The instrument panel module (IPM) monitors the initial signal that has been used by the brake pedal. When the engine control module (ECM) receives a serial data message from the instrument pedal module (IPM) indicating that the brake pedal has been applied, the scan tool displays Applied. Before the cruise control system is engaged, the engine control module (ECM) must receive a GMLAN serial data message from the IPM indicating that the brake pedal is pressed.

Internal Mode Switch: The scan tool displays Park, Park/Reverse, Reverse, Reverse/Neutral, Neutral, Neutral/Drive 4, Drive 4, Drive 4/Drive 3, Drive 3, Drive 3/Drive 2, Drive 2, Drive 2/Drive 1, Drive 1, INVALID and OPEN. The scan tool displays the physical position of the Internal Mode Switch (IMS) of the transmission.

MIL Requested by DTC: This parameter indicates the reason that the control module illuminated the MIL. The scan tool will display YES when the MIL is requested as a result of an A or B type DTC. The scan tool will display NO if the MIL is illuminated fro another reason, such as transmission DTCs.

Park/Neutral Position Switch: This parameter indicates the range selection of the automatic transmission as calculated by the control module based on input from the PNP switch. The scan tool will display, In Gear, Park, or Neutral depending on the PNP switch position.

Remote Vehicle Start (RVS) Disabled, History DTC (1-8): The scan tool indicates the disabled causes of the remote vehicle start (RVS).

Remote Vehicle Start (RVS) Request Signal: The scan tool displays On/Off. When the engine control module (ECM) receives the remote vehicle start (RVS) request signal, the scan tool displays On. If not so, it displays Off.

Starter Disabled: The scan tool displays Yes/No. The scan tool displays No unless vehicle theft deterrent has been activated then Yes is displayed.

Starter Relay Circuit Status: The scan tool displays Fault/OK/Invalid State. The scan tool displays Fault until the ignition is placed into the START position then OK is displayed.

Starter Relay Command: The scan tool displays ON/OFF. The scan tool displays Off until the ignition is placed into the CRANK position, then it reads ON.

Stop Lamp Pedal Switch: The scan tool displays Applied/Released. The ECM monitors the stop lamp pedal switch signal circuit. An activated brake pedal is displayed as Applied.

System Power Mode: This parameter displays the position of the ignition switch.

Vehicle Speed Sensor: This parameter indicates the vehicle speed as calculated by the control module based on a signal from the vehicle speed sensor (VSS). The scan tool will display a high value at high vehicle speed, and a low value at low vehicle speed.