code 42 on scanmaster

[wbzautocustomiz]

Code 42 means Bad ign coil? Bad ground? Help car stumbles at WOT

 

[TurboBuRick]

Copy paste

CODE 42

Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.

During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.

An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.

The conditions for setting this code are:

System in BYPASS mode but the ignition module is still controlling timing
- or -
Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.

Typical causes for this code include:

1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM

 

[wbzautocustomiz]

Next?

Car was ok til now so im thinkin something like a broken wire blown fuse so, If anyone can tell how to diagnose the EST , bypass, etc is this a wire that should read a certain voltage, etc? Help please

 

[gsgns4me]

Link--->DTC 42 Diagnosis

 

[XLR8]

The above link is an excellent flow chart to follow.
My code 42 was a bad module. You may want to try and borrow a known good module.

 

[psycho6cyl]

For me it was the white wire in the module harness. Its the same wire used to tap into w the translator. Repaired wire no more probs. I actually bought that bulk head from caspers just gotta find time todo it.