Circuit Description
The powertrain control module (PCM) supplies a voltage of about 0.45 volt to the oxygen sensor (O2S) 1. The O2S 1 varies the voltage between a range of about 1 volt if the exhaust is rich, down through about 0.10 volt if the exhaust is lean.
The O2S 1 is like an open circuit and produces no voltage when the O2S 1 temperature is below 315°C (600°F). An open O2S 1 circuit or cold sensor causes an Open Loop operation.
Conditions For Running The DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0169, P0171, P0172, P0178, P0179, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0446, P0452, P0453, P0506, P0507, P0601, P0602, or P1441 are not set. |
| • | The engine coolant temperature (ECT) is more than 70°C (158°F). |
| • | The engine run time more than 10 seconds. |
| • | The throttle position (TP) angle is between 8-50 percent. |
| • | The engine has met the above conditions for 3.8 seconds. |
| • | The fuel level more than 10 percent. |
| • | The system is in Closed Loop. |
| • | The system voltage more than 10 volts. |
| • | The fuel ethanol composition less than 88 percent. |
| • | The manifold absolute pressure (MAP) greater than 25 kPa. |
Conditions For Setting The DTC
O2S 1 voltage is more than 946 mV for 50 seconds.
Or
O2S 1 voltage is more than 1,042 mV for 2.5 seconds while in de-acceleration fuel control cut-off (DFCO).
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
The diagnostic trouble code (DTC) P0132 or the rich exhaust is most likely caused by one of the following conditions:
| • | The fuel pressure--The system will go rich if the fuel pressure is too high. The PCM can compensate for some increase. However, if the fuel pressure gets too high, a DTC P0132 will set. Refer to Fuel System Diagnosis . |
| • | A leaking injector--A leaking or faulty fuel injector can cause the system to go rich causing a DTC P0132. Refer to Fuel Injector Circuit Diagnosis . |
| • | The electronic ignition (EI) shielding--An open ground circuit may result in electromagnetic interference (EMI) or induced electrical noise. The PCM looks at this noise as 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. |
| • | The MAP sensor--An output that causes the PCM to sense a higher than normal manifold pressure or low vacuum, can cause the system to go rich. Disconnecting the MAP sensor 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 sensor is disconnected. |
| • | The TP sensor--An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating. |
| • | An O2S 1 contamination--Inspect the O2S 1 for silicone contamination from fuel or use of improper RTV sealant. The O2S 1 may have a white powdery coating and result in a high but false voltage signal, rich exhaust indication. The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem. |
| • | Whenever the O2S pigtail wiring, the connector or the terminal are damaged, replace the entire O2S assembly. Do not attempt to repair the wiring, the connectors or the terminals. In order for the sensor to function properly, the O2S 1 must have a clean air reference. The O2S wires obtains this clean air reference. Any attempt to repair the wires, the connectors or the terminals could result in the obstruction of the clean air reference. Any attempt to repair the wires, the connectors or the terminals could degrade the O2S performance. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if DTC P0132 is the result of a hard malfunction or an intermittent condition. You may need to operate the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction detected by the PCM.
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This step tests the circuit for a short to voltage. A shorted circuit will show voltage above 500 mV. The maximum O2S 1 reading the scan tool will show is just above 1,000 mV even if the actual short is a much higher voltage. The normal bias voltage is approximately 456 mV when the sensor is disconnected as read by the scan tool.
Step | Action | Values | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||||
Does the O2S 1 voltage measure more than the value specified? | 946 mV | Go to Step 4 | Go to Step 3 | |||||||||||
3 | This DTC is intermittent. Are any additional DTCs stored? | -- | Go to Diagnostic Aids | |||||||||||
Does the O2S 1 voltage measure above the specified value? | 500 mV | Go to Step 6 | Go to Step 5 | |||||||||||
5 | The O2S 1 is detecting a rich exhaust condition or may be contaminated. Check for one of the following conditions:
Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 | ||||||||||
6 | Test the high signal circuit of the O2S for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 | ||||||||||
7 |
Important: Before replacing a contaminated O2S 1 determine and repair the cause of the contamination. Replace the O2S 1. Refer to Oxygen Sensor Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||||
8 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||||
9 |
Does the DTC run and pass? | -- | Go to Step 10 | Go to Step 2 | ||||||||||
10 | With a scan tool, observe the stored information in Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||||
