P1133

Schematic:

CIRCUIT DESCRIPTION
The PCM monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this monitor period the PCM counts the number of times that the HO2S switches form rich to lean and lean to rich. A DTC P1133 sets when the PCM determines that the HO2S did not switch enough times.

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.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358, P0506, P0507, P1258 not set.
^ The fuel system is operating in Closed Loop.
^ The engine run time is more than 120 seconds.
^ The engine speed is more than 1,000 RPM but less than 2,300 RPM.
^ The ignition voltage is more than 9.0 volts.
^ The engine coolant temperature is more than 50°C (122°F).
^ The MAF is between 20 g/s and 50 g/s.
^ The EVAP purge duty cycle is more than 0 percent.

CONDITIONS FOR SETTING THE DTC
The PCM determines that within 100 seconds the HO2S lean to rich switches are less than 10 and rich to lean switches are less than 10.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the Malfunction Indicator Lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
^ For any test that requires probing the PCM or a component harness connector, use the J 35616-A connector test adapter kit. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.

Inspect the HO2S signal circuit for being shorted to a PCM ground. The HO2S signal circuit shorted to a PCM ground will not cause a HO2S low DTC to set, but will set a switching DTC.

A malfunction in the HO2S heater circuits will cause a DTC P1133 to set. Inspect the HO2S heater circuits for intermittent opens/connections. Refer to Testing for Intermittent and Poor Connections in Diagrams.

An oxygen supply inside the HO2S is necessary for proper operation. This supply of oxygen is provided through the HO2S wires. All HO2S wires and connections should be inspected for breaks or contamination. Refer to Heated Oxygen Sensor (HO2S) Wiring Repairs in Diagrams. For an intermittent condition, refer to Symptoms. Symptom Related Diagnostic Procedures

TEST DESCRIPTION

Steps 1 - 4:

Steps 6 - 15:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the fault is present. This test may take 5 minutes for the diagnostic to run.
3. When DTCs 1133 and P1153 are set at the same time, it is a good indication that a fuel contamination condition is present.
4. An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.
5. This step tests whether a good ground circuit is available.
6. This step tests the integrity of the signal circuit to the PCM.
7. This step tests the integrity of the signal circuit to the PCM.
8. Certain RTV silicone gasket materials give off vapors that can contaminate the HO2S. There is also a possibility of silicone contamination caused by silicone in the fuel. If the sensors appear to be contaminated by silicone and all the silicone sealant is a non silicone base, advise the customer to try a different fuel company. A missing fuel filler restrictor indicates the customer may have used leaded fuel.