Circuit Description
This diagnostic test checks for too few 4X reference pulses between CAM pulses. The PCM checks to see if there are forty-eight 24X reference pulses between CAM pulses, and if there are, the PCM assumes it is receiving valid CAM pulses. Therefore, if the PCM sees less than eight 4X reference pulses between CAM pulses, it sets DTC P1371, because the 4X reference signal must be faulty.
Conditions for Running the DTC
| • | The engine speed is more than 496 RPM. |
| • | At least 7 CAM pulses received since key ON. |
| • | At least one CAM pulse received in the last 0.25 second. |
| • | 48 24X reference pulses received between CAM pulses. |
Conditions for Setting the DTC
The PCM has received less than 8 4X reference pulses between CAM pulses.
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail. |
| • | A last test failed, or current DTC, will clear when the diagnostic runs and does not fail. |
| • | A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test. |
| • | Use a scan tool to clear DTCs. |
| • | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in Powertrain Control Module Description . |
Diagnostic Aids
An intermittent open or short to ground in CKT 430 may set this DTC. Inspect the terminals carefully.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Diagnose DTCs P0322 or P1320 first because those problems can cause P1371 to set.
-
This step is checking for possible cause of noise, missing 4X pulses, on the fuel control (4X) circuit.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |||||||||
Are DTCs P0322 or P1320 also set? | -- | Go to the DTCs that are set | Go to Step 3 | |||||||||
Was any possible source of EMI found and removed? | -- | Go to Step 7 | Go to Step 4 | |||||||||
4 | Clear DTCs and retest. Does DTC P1371 reset? | -- | Go to Step 5 | Go to Diagnostic Aids | ||||||||
5 |
Was a problem found and repaired? | -- | Go to Step 7 | Go to Step 6 | ||||||||
6 | Replace the ICM. Refer to Ignition Control Module Replacement . Is the repair complete? | -- | Go to Step 7 | -- | ||||||||
7 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||||||||||
8 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
