Chart D-1, Grounded Serial Data Circuit (Non-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 along circuit will be zero. Display on IPC will be ELECTRICAL PROBLEM and ECCP will display dashes "--".
NOTE:
Test numbers refer to numbers on diagnostic chart.
- This step splits system in half to help isolate the source of grounded serial data line. If taking PCM out of system allows both halves of serial data line to rise above one volt, the source of short has been located. The remaining steps of chart follow same pattern in that the 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 differentiates between a grounded wire or a ground in the device.