System Check Chart A-1: Data Circuit Problem
You have been directed to this chart from the diagnostic system check as a result of an odometer reading of "0" or "ERROR". This is a result of total loss of communication on circuit No. 800 due to a wiring or element problem, or an EEPROM problem.
NOTE:
The following step numbers refer to circled numbers on diagnostic chart. See Fig 1
. For circuit identification, see Fig 2
.
- The Assembly Line Data Link (ALDL) cover is one of the branches of circuit No. 800.
- This isolates a fault in the data circuit between ALDL cover and the programmer. If odometer continues to read zero mph, circuits 800A-D, the IPC, BCM, and CCDIC are suspect.
- This step will remove the problem if it is within the CCDIC or circuit 800A.
- This will isolate circuit 800D as the problem, if the actual mileage returns.
- This checks for faulty IPC, or circuit 800C.
- This isolates the condition to the BCM, circuits 800C or 800B.