code 42 where should i start looking ???

[Novacaine]

My car threw a code 42 and I checked the chip and changed the ecu since i had a spare and it still throws the code about 5 sec after starting, Where is the most likely place of the problem? I know its in the ignition but i dont have a extra ignition module to try. Basically im wondering if its a simple matter to test the IGN module or could the problem be somewhere else that i can test? Any help would be greatly appreciated...

 

[HellOnWheels]

Isn't a 42 code for the est module on the passenger side close to the BAR sensor.

 

[Matt McClung]

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