Chart B-2 Data Problem

Chart B-2 - Data Problem:

Wiring Diagram For Charts B-2, B-3, B-4, B-5 & B-6:

CHART B-2 - DATA PROBLEM

Test Description:

1. The "Electrical Problem" telltale in the IPC will come on if the IPC or CRTC has lost data. Since diagnostics cannot yet be accessed to isolate the fault, noting the speedometer display will verify if all communication is lost or, if the IPC is receiving data from the BCM. If the IPC is receiving data the speedometer displays zero, not blank.

2. If the ALDL cover is off, reinstall the cover and go back to Chart B-1. Because the IPC and BCM can exchange data, the data line cannot be shorted. Since the IPC speedometer displays zero the reason the "Electrical Problem" telltale is on is because the CRTC, not the IPC, has lost data. In order for this to occur, CKT 800H must be OK and there must be two opens in the data line, one on either side of the CRTC or the CRTC is at fault. To verify the integrity of the data line, remove the ALDL cover and jumper the data line to ground. If the data line is OK, the speedometer will go blank as jumpering the data line to ground will stop all communication.



3. If the speedometer did not go blank, there are two opens in the line. To locate the opens, removing the programmer connector and measuring voltage at Terminal T will verify CKT 800F. If the voltage is below one volt, CKT 800F must be open or, the open is in the CRTC.