DTC 75

DTC 75 PCM Serial Data Malfunction:

CIRCUIT DESCRIPTION
The serial communication data link is an asynchronous link between the PCM, the EBCM/EBTCM, and other system controllers.

DTC WILL SET WHEN
DTC 75 can be set any time the ignition is in "RUN." A malfunction exists if a message from the PCM has not been received for 7.0 seconds.

ACTION TAKEN
The "TRACTION OFF" indicator will illuminate, (if vehicle is equipped with TCS), and TCS is inhibited. A DTC is stored in ABS-only systems, but ABS is not disabled.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Determines if DTC 76 was also set. Proceed to that DTC first.
2. Determines whether DTC 75 was set by an intermittent or current condition.
3. The 39700 Pinout Box with the J 39700-25 adapter cable must be connected before this step is performed. This step determines whether this malfunction is in the UART Serial Data or the PCM.

DIAGNOSTIC AIDS
Possible Causes:
^ Open UART Circuit.
^ UART Circuit shorted to ground or voltage.
^ PCM not transmitting Data.

The malfunction may be intermittent. Try performing the tests shown while "wiggling" wiring and connectors; this can often cause the fault to appear.

PCM DTC P1573 will likely be set along with this DTC if the malfunction is a short to ground or voltage on the serial data circuit.

If ABS/TCS DTC 75 is set and a PCM DTC is not, the malfunction is likely to be an open between the EBCM/EBTCM and the PCM.

It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.