Refer to Engine Controls Schematics .
Circuit Description
The oxygen sensor (O2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The powertrain control module (PCM) supplies the O2S 1 with signal and return circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the O2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs leaner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the O2S signal voltage.
The O2S needs to be at a high temperature in order to produce a voltage. Once the O2S has reached operating temperature, the controls module monitors the O2S bias, or reference, voltage as well as the O2S signal voltage for Closed Loop fuel control. During normal Closed Loop fuel control operation, the PCM will add fuel (enrichen the mixture) when the O2S detects a lean exhaust content and subtract fuel (leans-out the mixture) when the O2S detects a rich exhaust condition.
This DTC determines if the O2S is functioning properly by checking for an adequate number of O2S voltage transitions above and below the bias range of 300-600 mV within a given time frame. This DTC sets when the PCM fails to detect a minimum number of voltage transitions above and below the bias range during the test period time frame.
Conditions For Running The DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0169, P0171, P0172, P0178, P0179, P0201, P0202, P0203, P0204, P0300, P0336, P0440, P0446, P0446, P0452, P0453, P0506, P0507, P0601, P0602, or P1441 are not set. |
| • | ECT is more than 70°C (158°F). |
| • | Engine run time more than 200 seconds. |
| • | TP is between 11 percent and 22 percent for auto trans, or 10.5 percent and 21.5 percent for manual trans. |
| • | RPM between 1600 and 2200 for auto trans. or 1900 and 2500 RPM for manual trans. |
| • | Fuel level is more than 10 percent . |
| • | EVAP PWM is more than 35.6 percent . |
| • | Engine is operating in Closed Loop. |
| • | Purge learned memory is more than approximately 0.86. |
| • | Fuel ethanol composition is less than 15 percent. |
Conditions For Setting The DTC
The average O2S 1 R/L sweep is more than 533 ms for auto trans, or 341 ms for manual trans.
The average O2S 1 L/R sweep is more than 971 ms for auto trans, or 1111 ms for manual trans.
Or
The average R/L added to the average L/R sweep is more than 971 ms for auto trans, or 1111 ms for manual trans.
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after 2 consecutive ignition cycles in which the diagnostic runs with the malfunction present. |
| • | The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers. |
| • | A history DTC stores. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm up cycles without a fault. |
| • | A scan tool can clear the DTCs. |
Diagnostic Aids
Important: Never solder the O2S wires. For proper wire and connector repairs, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Check for the following conditions:
| • | An improperly installed air cleaner outlet duct. |
| • | The air cleaner outlet duct for collapsed ducting, restrictions, or a missing or plugged air filter. |
| • | Throttle body and intake manifold vacuum leaks. |
| • | A damaged or blocked throttle body inlet. |
| • | Exhaust system for corrosion, leaks, or loose or missing hardware--Refer to Exhaust System Inspection in Engine Exhaust. |
| • | The O2S is installed securely and the pigtail harness is not contacting the exhaust manifold. |
| • | O2S contamination. |
| • | The vacuum hoses for splits, kinks and proper connections. |
| • | Excessive water or other contaminants in the fuel. |
| • | PCM sensor grounds that are clean, tight and properly positioned. |
Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, then refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
O2S contamination is indicated if multiple response, switching or time ratio O2S DTCs are set.
-
The use of leaded fuel may be indicated by evidence of the removal or tampering of the fuel filter restrictor.
An O2S contaminated by silicon will have a white, powdery deposit on the portion of the O2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of an unapproved silicon room-temperature vulcanizing (RTV) engine gasket material, or the use of silicon-based sprays or fluids within the engine.
If the cause of this contamination is not corrected, the replacement O2S will also become contaminated.
-
Even small exhaust leaks can cause slow response from the O2S.
-
An O2S contaminated by silicon will have a white, powdery deposit on the portion of the O2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of an unapproved silicon RTV engine gasket material or the use of the use of silicon-based sprays or fluids within the engine. If the cause of this contamination is not corrected, the replacement O2S will also become contaminated.
-
If the voltage observed in step 8 is less than the range specified, a short between the HIGH and LOW circuits or a short between the HIGH circuit and ground is indicated. With the O2S and the PCM disconnected the resistance between the HIGH and LOW circuits and the resistance between the HIGH circuit and ground should measure infinite.
If the voltage observed in step 8 is more than the range specified, a short between the HIGH circuit and an ignition voltage source is indicated.
-
If the voltage observed in step 9 is not less than the voltage, specified a high resistance (open) HIGH or LOW circuit is indicated.
Good circuit continuity measures less than 5 ohms with the PCM and sensor disconnected. Measure between the PCM connector and the O2S connector. Ensure that the PCM terminal contact is good.
Step | Action | Values | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||||
Do the parameters show averages above the specified value in the Conditions for Setting the DTC? | -- | |||||||||||||
3 | Are any powertrain component DTCs set? | -- | Go to applicable DTC table | |||||||||||
Has the contamination source been removed and the affected sensor replaced? | -- | -- | ||||||||||||
5 |
| -- | ||||||||||||
6 | This DTC is intermittent. Are any additional DTCs stored? | -- | Go to applicable DTC table | Go to Diagnostic Aids | ||||||||||
Repair exhaust as necessary. Refer to Exhaust System Inspection in Engine Exhaust. Did you find a condition? | -- | |||||||||||||
8 |
Is the O2S1 voltage near the value specified? | 447 mV | ||||||||||||
9 |
Is the O2S 1 voltage less than the value specified? | 20 mV | ||||||||||||
10 |
O2S 1 contamination sources include the following:
Is the action complete? | -- | -- | |||||||||||
11 | Repair the short between the O2S 1 signal and low circuits or between the O2S signal circuit and a voltage source. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||||
Is the action complete? | -- | -- | ||||||||||||
Replace the O2S 1. Refer to Oxygen Sensor Replacement . Is the action complete? | -- | -- | ||||||||||||
Does the scan tool indicate the diagnostic Passed? | -- | |||||||||||||
15 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to applicable table | System OK |
