Test Description
WARNING: This page is about a different variant/trim than selected.
The numbers below refer to the step numbers on the diagnostic table.
- 2: When the system is operating correctly, the HO2S 2 voltage should toggle above and below the bias voltage.
- 5: This step tests the HO2S 2 high signal circuit for a short to voltage.
DTC P0138
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views |
||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | - | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 |
|
1,042 mV | Go to Step 4 | Go to Step 3 |
| 3 |
|
- | Go to Step 4 | Go to Intermittent Conditions |
| 4 |
|
350-550 mV | Go to Step 6 | Go to Step 5 |
| 5 | Test the HO2S 2 high signal circuit for a short to voltage. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
- | Go to Step 11 | Go to Step 8 |
| 6 |
|
- | Go to Step 11 | Go to Step 7 |
| 7 | Inspect for poor connections at the harness connector of the HO2S 2. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
s. Did you find and correct the condition? |
- | Go to Step 11 | Go to Step 9 |
| 8 | Inspect for poor connections at the harness connector of the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
- | Go to Step 11 | Go to Step 10 |
| 9 |
IMPORTANT:
Before replacing a contaminated HO2S, determine and repair the cause of the contamination. Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2
.Did you complete the replacement? |
- | Go to Step 11 | - |
| 10 | Replace the ECM. Refer to Control Module References
for replacement, setup, and programming. Did you complete the replacement? |
- | Go to Step 11 | - |
| 11 |
|
- | Go to Step 2 | Go to Step 12 |
| 12 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? |
- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |