Diagnostic Aids
- Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
- If the vehicle has set overnight, the ECT sensor and the intake air temperature (IAT) sensor values should display within 3°C (5°F). Refer to TEMPERATURE VS RESISTANCE .
- For an intermittent condition, refer to Intermittent Conditions .
DTC P0118
| 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 - Engine Controls? | - | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 |
IMPORTANT:
The cooling fans are commanded ON when certain DTCs are set.
|
-39°C (-38°F) | Go to Step 4 | Go to Step 3 |
| 3 |
|
- | Go to Step 4 | Go to Diagnostic Aids |
| 4 |
|
5.2 V | Go to Step 5 | Go to Step 6 |
| 5 |
IMPORTANT:
The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage. Test the ECT sensor signal circuit for a short to voltage. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems.Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 12 |
| 6 |
|
214°C 417°F) | Go to Step 10 | Go to Step 7 |
| 7 |
|
214°C (417°F) | Go to Step 9 | Go to Step 8 |
| 8 | Test the signal circuit of the ECT sensor for an open or for a high resistance. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 12 |
| 9 |
IMPORTANT:
Test the ECT sensor low reference circuit for an open, for a high resistance, or for a short to voltage. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems.Did you find and correct the condition?
|
- | Go to Step 15 | Go to Step 12 |
| 10 | Test the ECT signal circuit for a short to any 5-volt reference circuit. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 11 |
| 11 | Test for an intermittent and for a poor connection at the ECT sensor. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 13 |
| 12 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 14 |
| 13 |
IMPORTANT:
If a short to voltage occurs, the ECT sensor may be damaged. Replace the ECT sensor. Refer to Engine Coolant Temperature (ECT) Sensor Replacement
.Did you complete the replacement? |
- | Go to Step 15 | - |
| 14 | Replace the ECM. Refer to Engine Control Module (ECM) Replacement
. Did you complete the replacement? |
- | Go to Step 15 | - |
| 15 |
|
- | Go to Step 2 | Go to Step 16 |
| 16 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? |
- | Go to Diagnostic Trouble Code (DTC) List | System OK |