DTC 42

Fig. 010 - WIRING DIAGRAM for Code 42 Electronic Spark Timing. VIN W:

CODE 42

ELECTRONIC SPARK TIMING (EST)

2.8L "X" SERIES

FUEL INJECTION (PORT)

Code 42 means the ECM has seen an open or short to ground in the EST or by-pass circuits.

Fig. 009 - Chart - Code 42 Electronic Spark Timing:

1. Confirms Code 42 and that the Fault causing the code is present.
2. Checks for a normal EST ground path through the ignition module. An EST CKT 423 shorted to ground will also read less than 500 ohms; however, this will be checked later.
3. As the test light voltage touches CKT 424, the module should switch causing the ohmmeter to "overrange" if the meter is in the 1000-2000 ohms position.

Selecting the 10-20,000 ohms position will indicate above 5000 ohms. The important thing is that the module "switched".

4. The module did not switch and this stepchecks for:
a. EST CKT 423 shorted to ground.
b. Bypass CKT 424 open.
c. Faulty ignition module connection or module.
5. Confirms that Code 42 is a faulty ECM and not an intermittent in CKTS 423 or 424.