P1134

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The PCM monitors the Heated Oxygen Sensor (HO2S) activity. During the monitor period the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. The PCM then divides the rich to lean average by the lean to rich average to obtain a ratio. If the HO2S ratio is not within range, a DTC P1134 will be set.

CONDITIONS FOR SETTING THE DTC

DTCs P0100, P0102, P0103, P0107, P0108, P0117, P0118, P0125, P0200, P0372 not set.

^ System operating in Closed Loop

^ Engine speed greater than 1000 RPM but less than 1700 RPM.

^ MAF between 12 gm/s and 28 gm/s.

^ The PCM determines that the HO2S transition time ratio is not at the expected value.

ACTION TAKEN WHEN THE DTC SETS

^ The DTC will be stored in the PCM memory when the diagnostic runs and fails.

^ The Malfunction Indicator Lamp (MIL) will not illuminate.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC

^ A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

^ A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.

^ PCM battery voltage is interrupted.

^ Using a scan tool.

DIAGNOSTIC AIDS

^ Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed.

^ 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.

For intermittents, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. Determines if the fault is present. This test may take 5 minutes for the diagnostic to run.

3. When DTCs P1134 and P1154 are set at the same time, is good indication that a fuel contamination problem is present.

4. An exhaust leak 6 to 12 inches away from the HO2S can cause a DTC to set.

6. Checks whether a good ground circuit is available.

7. Checks 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 fuel. If it appears that the sensors are contaminated by silicon and all silicone sealant is a none silicone base, advise customer to try a different fuel company. A fuel filler restrictor missing. indicates leaded fuel may have been used.