Circuit Description
The powertrain control module (PCM) monitors the heated oxygen sensor (HO2S) activity. During the monitoring period the PCM counts the number of times that the HO2S responds from rich to lean, and from lean to rich, and adds the time used to complete all transitions. With this information, the PCM can determine an average time for all transitions. The PCM then divides the rich to lean average by the lean to rich average in order to obtain a ratio. If the HO2S ratio is not within range, a DTC will set. This diagnostic runs once per ignition cycle.
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0131, P0132, P0134, P0135, P0151, P0154, P0155, P0200, P0300, P0410, P0440, P0442, P0446, P0452, P0453, P1120, P1125, P1220, P1221, P1258, P1415, P1416, P1441, P1514, P1515, P1516, P1517, or P1518 are not set. |
| • | The loop status is Closed. |
| • | The engine run time is more than 160 seconds. |
| • | The engine speed is between 1,000-2,300 RPM. |
| • | The ignition 1 signal is between 9-18 volts. |
| • | The engine coolant temperature (ECT) is more than 50°C (122°F). |
| • | The evaporative emissions (EVAP) purge solenoid is more than 0 percent. |
| • | The mass air flow (MAF) is between 18-50 g/s. |
| • | The throttle position (TP) indicated angle is 5 percent more than the value observed at idle. |
| • | The fuel tank level remaining is more than 10 percent. |
| • | The above conditions are met for 60 seconds. |
Conditions for Setting the DTC
The PCM determines that the HO2S transition time ratio is more than or less than the calibrated range.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Important:
• Before you service the PCM, remove any debris from the PCM connector
surfaces. Inspect the PCM connector gaskets when you diagnose or
replace the module. Verify that the gaskets are correctly installed.
The gaskets prevent contaminate intrusion into the PCM. • For any test that requires probing the PCM or probing
a component harness connector, use the connector test adapter kit J 35616
. Using this kit
prevents damage to the harness and component terminals. Refer
to
Using Connector Test Adapters
in
Wiring Systems.
| • | An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide this oxygen supply. Inspect all HO2S wires and connections for breaks or for contamination. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems. |
| • | For an intermittent, refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the fault is present. This test may take 5 minutes for the diagnostic test to run.
-
When DTCs P1134 and P1154 are set at the same time, a fuel contamination condition is present.
-
An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.
-
This step verifies whether a good ground circuit is available.
-
This step verifies the integrity of the signal circuit to the PCM.
-
This step verifies the integrity of the signal circuit to the PCM.
-
Certain room-temperature vulcanizing (RTV) silicone gasket materials release vapors that can contaminate the HO2S. Silicone in the fuel can cause silicon contamination. If the sensors appear contaminated by silicone, and if all of the silicone sealant is a non-silicone base, advise the customer to try a different fuel company.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||
|
Important: If any DTCs except DTC P1134 or P1154 set, refer to those DTCs before proceeding with this diagnostic table.
Did DTC P1134 or P1154 fail this ignition? | -- | Go to Step 3 | Go to Diagnostic Aids | |||||||||
Did both DTC P1134 and P1154 fail this ignition? | -- | Go to Step 8 | Go to Step 4 | |||||||||
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 5 | |||||||||
Inspect the following conditions:
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 6 | |||||||||
Is the voltage within the specified range? | 350-550 mV | Go to Step 7 | Go to Step 10 | |||||||||
Is the voltage less than the specified value? | 200 mV | Go to Step 13 | Go to Step 9 | |||||||||
|
Important: Determine and correct the cause of the contamination before replacing
a sensor. Inspect for the following conditions:
Replace the affected heated oxygen sensor-- Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , or refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Did you complete the replacement? | -- | Go to Step 14 | -- | |||||||||
9 |
Is the voltage near the specified value? | 5 V | Go to Step 12 | Go to Step 11 | ||||||||
10 | Repair the high signal circuit for a short to ground or for a short to voltage. Refer to Wiring Repairs in Wiring Systems . Did you complete the repair? | -- | Go to Step 14 | -- | ||||||||
11 | Repair the open in the HO2S low signal circuit, or repair the poor PCM connections. Refer to Wiring Repairs in Wiring Systems . Did you complete the repair? | -- | Go to Step 14 | -- | ||||||||
12 | Repair the HO2S high signal circuit for an open, or repair the poor PCM connections. Refer to Wiring Repairs in Wiring Systems . Did you complete the repair? | -- | Go to Step 14 | -- | ||||||||
13 | Replace the affected HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Did you complete the replacement? | -- | Go to Step 14 | -- | ||||||||
14 |
Does the DTC run and pass? | -- | Go to Step 15 | Go to Step 2 | ||||||||
15 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||
