42 code on scanmaster

84sithlord

Member
Joined
May 3, 2011
My scanmaster flagged a 42 code consistently this morning. My car has been having trouble starting on an irregular basis. thought i might have a hung injector but i don't think thats the case. it finally flagged the 42 code. I also noticed a new oil leak as well....any insight? shut car off to go in store, on restart code cleared. :confused:
 
Try this link for additional info-

Malfunction Codes Reference

Code 42 shows a C3I ELECTRONIC SPARK TIMING (EST) FAILURE

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
 
Top