PCM Messages Not Received

PCM MESSAGES NOT RECEIVED

PCM Messages Not Received:

WHEN MONITORED
With the ignition on.

SET CONDITION
The MIC does not receive any messages from the PCM for atleast 5 seconds.

POSSIBLE CAUSES
- (D25) PCI BUS circuit open
- Powertrain control module

1. PCM MESSAGES NOT RECEIVED
Turn the ignition on.

NOTE: To proceed in this test, the DTC must be active.

With the DRB, enter SYSTEM MONITORS then J1850 MODULE SCAN.

Q: Is the PCM active on the BUS?

YES: Check the condition of the J1850 Bus circuit wiring. Erase DTC, if DTC resets replace the Instrument Cluster. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 2

2. ATTEMPT TO COMMUNICATE WITH THE PCM
Turn the ignition on.
With the DRB, attempt to communicate with the PCM.

Q: Was the DRB able to communicate with the PCM?

YES: Go To 3
NO: Refer to the communication category and perform the appropriate symptom. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

3. CHECK THE (D25) PCI BUS CIRCUIT FOR AN OPEN




Turn the ignition off.
Disconnect the PCM harness connector.

CAUTION: If NGC, do not probe the PCM harness connectors. probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. install miller special tool #8815 to perform diagnosis.

Disconnect the DRBIII(R) from the DLC.
Measure the resistance of the (D25) PCI Bus circuit between the PCM connector (from special tool #8815 if NGC) and the DLC.

Q: Is the resistance below 5.0 ohms?

YES: Replace and program the Powertrain Control Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (D25) PCI Bus circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test