The powertrain control module (PCM) monitors the heated oxygen sensor (HO2S) activity for 100 seconds. During this test period, the PCM counts the number of times that the HO2S signal voltage crosses the rich to lean and lean to rich thresholds. If the PCM determines that the HO2S did not switch enough times, DTC P1133 will be set. A lean to rich switch is determined when the HO2S voltage changes from less than 300 mV to more than 600 mV. A rich to lean switch is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV.
• | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300, P0410, P0412, P0418, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1114, P1115, P1121, P1122, P1441, P0131, P0132 or P0135 are not set |
• | The system voltage is more than 9 volts. |
• | The engine is running in Closed Loop |
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• | The engine is running for at least 4 minutes. |
• | The engine cooling temperature (ECT) is more than 75°C (167°F). |
• | The transmission is in drive. |
• | The engine speed is between 1,200-2,300 RPM. |
• | The mass air flow (MAF) is between 15-35 g/s. |
• | The above conditions are stable for 3 seconds. |
• | The above conditions are present for a 90 second monitoring period. |
• | The PCM monitors fewer than 5 rich to lean and 5 lean to rich switches for HO2S 1. |
• | 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. |
• | 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. |
Notice: Use the connector test adapter kit J 35616-A for any test that
requires probing the following items:
• The PCM harness connectors • The electrical center fuse/relay cavities • The component terminals • The component harness connector
A malfunction in the HO2S heater ignition feed or ground circuit may cause the DTC to set. Inspect the HO2S heater circuitry for intermittent malfunctions or poor connections. If connections and wiring are OK and the DTC continues to set, the HO2S may be at fault.
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.
If the problem is intermittent, refer to Intermittent Conditions .
The numbers below refer to the step numbers on the diagnostic table.
This step verifies correct sensor activity. When in Closed Loop fuel control, the HO2S voltage should rapidly swing above and below the bias voltage.
This step inspects the PCM and the high and low circuits between the PCM and the HO2S connector for correct operation.
This step inspects for correct HO2S heater circuit operation up to the HO2S connector.
This step inspects for correct circuit resistance between the HO2S low reference circuit and the PCM ground.
This step inspects for proper circuit resistance between the HO2S low reference circuit and the PCM ground with a COLD sensor. A loose HO2S or faulty thread to exhaust electrical contact will cause higher resistance when the HO2S is cold. Although 500 ohms is allowed, typical resistance should be less than 50 ohms.
Step | Action | Values | Yes | No | ||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||||||||||||
Is the HO2S voltage fixed within the voltage range specified? | 351-551 mV | Go to Step 4 | Go to Step 3 | |||||||||||||||||||
3 |
Was a condition found and repaired? | -- | Go to Step 17 | Go to Diagnostic Aids | ||||||||||||||||||
Is the HO2S voltage less than the value specified? | 20 mV | Go to Step 7 | Go to Step 5 | |||||||||||||||||||
5 |
Is the individual resistance of both circuits less than the specified value? | 5 ohms | Go to Step 6 | Go to Step 9 | ||||||||||||||||||
6 |
Was a PCM terminal repair made? | -- | Go to Step 17 | Go to Step 16 | ||||||||||||||||||
Is the test lamp illuminated? | -- | Go to Step 8 | Go to Step 10 | |||||||||||||||||||
Is the resistance measured less than the value specified? | 500 ohms | Go to Step 12 | Go to Step 11 | |||||||||||||||||||
9 | Repair the circuit that measured high resistance. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 17 | -- | ||||||||||||||||||
10 | Repair the HO2S ignition 1 voltage or HO2S heater low control circuit. Refer to Wiring Repairs in Wiring Systems. Probable causes of the condition include the following:
Is the action complete? | -- | Go to Step 17 | -- | ||||||||||||||||||
11 | Repair the high resistance between the HO2S low reference circuits and the PCM ground circuit. Refer to Wiring Repairs in Wiring Systems. Probable causes of the condition include the following:
Is the action complete? | -- | Go to Step 17 | -- | ||||||||||||||||||
12 |
The leak may be very small and will typically will be within 304 mm (12 inches) of the suspect HO2S. Was an exhaust system repair made? | -- | Go to Step 17 | Go to Step 13 | ||||||||||||||||||
Is the resistance less than the value specified? | 500 ohms | Go to Step 15 | Go to Step 14 | |||||||||||||||||||
14 |
Is the resistance less than the value specified? | 500 ohms | Go to Step 17 | Go to Step 15 | ||||||||||||||||||
15 | Replace the HO2S. Refer to Heated Oxygen Sensor 1 Replacement . Is the action complete? | -- | Go to Step 17 | -- | ||||||||||||||||||
16 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 17 | -- | ||||||||||||||||||
17 |
Does the DTC run and pass? | -- | Go to Step 18 | Go to Step 2 | ||||||||||||||||||
18 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |