Circuit Description
The Powertrain Control Module (PCM) supplies a voltage of about 0.45 volt between the Oxygen Sensor (O2S 1) signal and the ground circuit. The Oxygen Sensor (O2S 1) varies the voltage within a range of about 1 volt if the exhaust is rich, down through about 0.10 volt if the exhaust is lean.
The sensor is like an open circuit and produces no voltage when below 315°C (600°F). An open sensor circuit or a cold sensor causes an Open Loop operation.
Replace the entire oxygen sensor (O2S 1) assembly. Do not attempt to repair the oxygen sensor if the following conditions exist:
| • | Damaged wiring |
| • | Damaged electrical connector |
| • | Damaged terminals |
Conditions For Running The DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 not set. |
| • | Air flow is more than 3 grams per second. |
| • | Engine Coolant Temperature (ECT) is more than 70°C (158°F). |
| • | Engine is operating in Closed Loop. |
| • | Throttle Position (TP) angle is between 5 percent and 50 percent. |
| • | Engine has met the above conditions for 30 seconds. |
Conditions For Setting The DTC
O2S 1 voltage is more than 946 mV for 50 seconds.
Or
O2S 1 voltage is more than 1042 mV for 50 seconds while in deceleration mode.
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active. |
| • | 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. |
| • | The coolant fan turns ON. |
| • | The vehicle will operate in an Open Loop operation. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after three 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. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
The DTC P0132 or rich exhaust is most likely caused by one of the following items:
| • | Fuel pressure -- The system will go rich if fuel pressure is to high. The PCM can compensate for some increase, however, if it gets too high, a DTC P0132 will be set. Refer to the Fuel System Diagnosis . |
| • | Leaking injector -- A leaking or malfunctioning injector can cause the system to go rich causing a DTC P0132. Refer to the Fuel Injector Balance Test 2.4L. |
| • | Electronic Ignition (EI) shielding -- An open ICM reference low circuit may result in a EMI or induced electrical noise. The PCM looks at this noise as a Crankshaft Position (CKP) sensor pulses. The additional pulses result in a higher than actual engine speed signal. The PCM then delivers too much fuel causing the system to go rich. The engine tachometer will also show higher than actual engine speed which can help in diagnosing this problem. |
| • | MAP sensor -- An output that causes the PCM to sense a higher than normal manifold pressure, or a low vacuum, can cause the system to go rich. Disconnecting the MAP sensor electrical connector --will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the MAP sensor is disconnected. |
| • | Pressure regulator -- Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the fuel pressure regulator. |
| • | TP sensor -- An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating. |
| • | O2S 1 contamination -- Inspect the O2S 1 sensor for silicone contamination from fuel or the use of improper RTV sealant. The O2S 1 sensor may have a white powdery coating and this will result in a high but false voltage signal, indicating a rich exhaust. The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem. |
Test Description
The numbers below refer to step numbers on the diagnostic table:
-
This DTC failing during deceleration fuel mode operation, when the vehicle speed is more than 25 mph, and the TP angle is less than 3 percent, may indicate a condition described in Diagnostic Aids. If this DTC test passes while the Fail Records conditions are being duplicated, an intermittent condition is indicated. Review the Fail Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
-
This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Does the voltage remain above the specified value? | 946 mV | ||
Operate vehicle in Decel fuel mode (vehicle speed above 25 mph, TP angle below 3%) while observing the O2 voltage parameter on the scan tool. Does the voltage remain above the specified value while in Decel fuel mode? | 110 mV | |||
4 | Operate the vehicle within the Fail Records conditions. Does the scan tool indicate this DTC failed this ignition? | -- | Go to Diagnostic Aids | |
5 | Disconnect the O2. Does scan tool indicate O2 voltage more than the specified value? | 500 mV | ||
6 | Test for a short to voltage on the signal circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | ||
|
Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the repair? | -- | -- | ||
8 | Inspect the vehicle for any of the conditions in Diagnostic Aids. If no problem is found, replace the O2. Refer to Oxygen Sensor Replacement . Did you complete the repair? | -- | -- | |
9 |
Does the DTC reset? | -- | System OK |
