Chart D-1, Grounded Serial Data Circuit (CRT Equipped)
NOTE:
The Electronic Control Module (ECM) may be referred to as the Powertrain Control Module (PCM) in diagnostic charts and figures. The 2 terms may be used interchangeably.
With grounded serial data circuit, BCM will not be able to communicate with any other devices in system. Voltage measured anywhere in circuit will be zero. IPC display will show ELECTRICAL PROBLEM, CRT will display normally and HVAC controls will not function.
NOTE:
Test numbers refer to numbers on diagnostic chart.
- This step splits the system in half to help isolate source of grounded serial data line. If taking PCM out of the system allows both halves of serial data line to rise above one volt, source of short has been located. The remaining steps follow same pattern in that components are removed from serial data line until normal voltage range is again measured. When section of circuit is isolated, a simple check of wire for short to ground will differentiate between grounded wire or ground in a device remote.