Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: The rough road sensor will give correct voltages only if it is level and mounted securely to its bracket.
- 12: This step tests for poor connection at the ECM or the harness connections for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection.
DTC P1391
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: 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 | Inspect for the following conditions and repair as needed:
Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 3 |
| 3 |
|
1.1-3.7 V | Go to Step 4 | Go to Step 5 |
| 4 |
|
- | Go to Step 5 | Go to Intermittent Conditions |
| 5 |
|
0.1 V | Go to Step 6 | Go to Step 9 |
| 6 | Measure the voltage from the 5-volt reference circuit of the rough road sensor to a good ground with a DMM. Is the voltage less than the specified value? |
5.2 V | Go to Step 7 | Go to Step 10 |
| 7 | Measure the resistance between the low reference circuit of the rough road sensor and the ECM housing with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Is the resistance less than the specified value? |
2 Ω | Go to Step 11 | Go to Step 8 |
| 8 | Test the low reference circuit of the rough road sensor for a high resistance or an open. Refer to Circuit Testing
andWiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 12 |
| 9 | Test the signal circuit of the rough road sensor 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 |
IMPORTANT:
The 5-volt reference circuits are internally and externally connected at the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors. Test the 5 volt reference circuit of the rough road sensor 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 |
| 11 | Test for shorted terminals and for poor connection at the rough road 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 shorted terminals and for poor connections 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 | Replace the rough road sensor. 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 |