C1221

C1221-86-PCM BUS SIGNAL INVALID

For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
Continuously when the ignition is on.

The battery voltage between 10 and 16 Volts.

Body Control Module (BCM) is configured correctly.

- Set Condition:
Bus messages not received from the Powertrain Control Module (PCM) for approximately two to five seconds.





VERIFY THE DTC IS ACTIVE

NOTE: Make sure the battery is fully charged before proceeding.

1. Turn the ignition on.
2. With the scan tool, read the DTCs.

Is the DTC active at this time?

Yes

- Perform the U1701-87-Lost Communication with PCM diagnostic procedure U1701-87.

No

- Perform the Stored Lost Communication DTCs diagnostic procedure Stored Lost Communication DTCs.