Circuit Description
The powertrain control module (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, indicating that the oxygen sensor is not responding as expected to changes in exhaust oxygen content DTC P1134 will set.
Conditions for Running the DTC
| • | No TP Sensor, EVAP System, Misfire, IAT Sensor, MAP Sensor, Fuel Trim, Injector Circuit, EGR Pintle Position, MAF Sensor, ECT Sensor, CKP Sensor, or H02S Sensor 1 Heater Circuit DTCs set. |
| • | Mass air flow is between 10-30 g/s. |
| • | ECT is more than 50°C (122°F). |
| • | Engine run time is more than 60 seconds. |
| • | Engine speed is between 1000-3000 RPM. |
| • | The engine is running in Closed Loop. |
Conditions for Setting the DTC
| • | Above conditions present for a 100 second monitoring period. |
| • | VIN K - Ratio of average response times is not between 3.5-0.5. |
| • | VIN 1 - Ratio of average response times is not between 6-0.5. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has 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 a scan tool. |
Diagnostic Aids
A malfunction in the HO2S heater ignition feed or ground circuit may cause the DTC to set. Inspect 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.
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step test for conditions which may cause the DTC to set with a good heated oxygen sensor. Correct any of the described conditions if present.
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Before replacing the HO2S, inspect for silicon contamination. Refer to Silicon Contamination of Heated Oxygen Sensors Notice.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||||||||||
2 |
Important:: If any DTCs are set, except P1133 or P1134, go to those DTCs before proceeding.
Does the DTC reset? | -- | Go to Diagnostic Aids | |||||||||
3 |
Did you find and correct the condition? | -- | ||||||||||
Visually and physically inspect the following items:
Did you find any condition? | -- | |||||||||||
5 |
Does the voltage measure near the specified value? | 450 mV | ||||||||||
6 |
Does the voltage measure less than the specified value? | 300 mV | ||||||||||
Replace affected heated oxygen sensors. Refer to Heated Oxygen Sensor Replacement . Is the action complete? | -- | -- | ||||||||||
8 | Repair condition as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||
9 | Repair open HO2S 1 low signal circuit or grounded HO2S 1 high signal circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||
10 | Repair open HO2S 1 high signal circuit or poor connections at the PCM. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||
11 |
Does the DTC reset? | -- | System OK |
