P1134

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 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 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 active fuel trim, fuel injector circuit, Misfire, EVAP, EGR, AIR, TP, IAT, MAP, ECT, CKP, or MAF sensor DTCs present.
^ P0131, P0132 or P0135 not set
^ System voltage is greater than 9 volts.
^ Closed Loop
^ Engine running for at least 3.3 minutes.
^ ECT greater than 75°C (167°F)
^ Engine speed between 1000 and 3000 RPM
^ MAF between 15 and 40 gm/s
^ Above conditions stable for 3 seconds

Conditions for Setting the DTC
The PCM detects degraded (slow) rich to lean or lean to rich response times for HO2S 1.

Action Taken When the DTC Sets
^ The PCM illuminates the Malfunction Indicator Lamp 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 MIL Off after three consecutive drive trips that the diagnostic runs and does not tail.
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after forty 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.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Conditions for Clearing the MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

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
Using this kit will prevent damage caused by the improper probing of connector terminals.
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. If connections and wiring are OK and the DTC continues to set, replace the HO2S 1. 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.
The Heated Oxygen Sensors require an air reference (outside air) for proper operation. The air reference is supplied through the HO2S wiring. Inspect the HO2S wires and connections for breaks or contamination. Do not use solder to repair HO2S wiring. Solder will obstruct the air path.

Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
2. HO2S contamination may cause multiple HO2S DTCs to set.
4. The use of leaded fuel may be indicated by the removal or tampering of the fuel filler restrictor.
An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved silicon RTV engine gasket material, the use of silicon based sprays or fluids within the engine or coolant consumption. Phosphorus contamination also leaves a white powdery coating on the HO2S. Phosphorus contamination comes from oil consumption. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.
7. Even small exhaust leaks can cause slow response from the HO2S.
12. An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved silicon RTV engine gasket material, the use of silicon based sprays or fluids within the engine or coolant consumption. Phosphorus contamination also leaves a white powdery coating on the HO2S. Phosphorus contamination comes from oil consumption. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.
13. If the voltage observed in Step 8 is less than the range specified a short between the High and Low circuits or a short between the High circuit and ground is indicated. With the HO2S and the PCM disconnected the resistance between the High and Low circuits and the resistance between the High circuit and ground should measure infinite.
If the voltage observed in Step 8 is greater than the range specified a short between the High circuit and an ignition voltage source is indicated.
14. If the voltage observed in Step 9 is not below the voltage specified a high resistance (open) High or Low circuit is indicated.
Good circuit continuity measures less than 5 ohms with the PCM and sensor disconnected. Measure between the PCM connector and the HO2S connector. Ensure PCM terminal contact is good.