P1134

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The PCM continuously monitors the heated oxygen sensor (HO2S) activity for 100 seconds. During the monitor period the PCM counts the number of times that the HO2S varies 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 transition time ratio is not within range, DTC P1134 will be set, indicating that the oxygen sensor is not responding as expected to changes in exhaust oxygen content.

CONDITIONS FOR RUNNING THE DTC
^ No throttle position (TP) sensor, evaporative emission (EVAP) system, misfire, intake air temperature (IAT) sensor, manifold absolute pressure (MAP) sensor, fuel trim, injector circuit, exhaust gas recirculation (EGR) pintle position, mass air flow (MAF) sensor, engine coolant temperature (ECT) sensor, crankshaft position (CKP) sensor, or heated oxygen sensor (HO2S) 1 heater circuit DTCs are set.
^ The mass air flow is between 10-30 g/s.
^ The engine coolant temperature (ECT) is more than 50°C (122°F).
^ The engine run time is more than 60 seconds.
^ The engine speed is between 1000-3000 RPM.
^ The engine is running in closed loop.

CONDITIONS FOR SETTING THE DTC
^ The above conditions present for a 100 second monitoring period.
^ The ratio of average response times is not between 4.5-0.5.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the MIL during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions that were present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS
A malfunction in the HO2S heater ignition feed or ground circuit may cause the DTC to set. Check HO2S heater circuitry for intermittent malfunctions or poor connections. It the connections and wiring are OK and the DTC continues to set, replace the HO2S 1.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

TEST DESCRIPTION
Numbers below refer to the step numbers on the Diagnostic Table.
4. This step checks for conditions which may cause the DTC to set with a good heated oxygen sensor. Correct any of the described conditions if present.
7. Before replacing the HO2S, check for silicon contamination. Refer to Silicon Contamination of Heated Oxygen Sensors Notice.