92 Gmc Jimmy 4.3 Vin W Code 42

ENGINEMAN1 · March 13, 2008

HELLO TO ALL. I'M HAVING A MAJOR ISSUE WITH MY TRUCK WHERE IMMEDIATLY AFTER ABOUT 2 SECONDS FROM STARTING IT, IT SHOOTS ME THE GLORIOUS CODE 42. IT NEVER FAILS. I CAN EVEN CLEAR THE CODE AND EVERTHING BUT STILL NO MATTER WHAT STILL HAPPENS TO COME ON EVERY SINGLE TIME AFTER ABOUT TWO SECONDS AFTER TURNING IT ON. TRIED A NEW IGNITION CONTROL MODULE AND NO LUCK, TRIED NEW ECM AND NO LUCK. IT HAS A NEW DISTRIBUTOR AND ECM. CAR IS VERY DRIVEABLE BUT THAT IS ONLY BECAUSE ITS RUNNING ON BASE TIMING FROM ECM. I HAD PREVIOUSLY HAD A MAJOR ISSUE WITH THE ECM WHICH ENDED UP BEING REPLACED, SO AS I'M PUTTING THE ECM BACK IN ITS LOCATION, I DECIDED TO GO AHEAD AND REPLACE THE INSTRUMENT CLUSTER BULBS WHICH EVERY ONE WAS PRETTY MUCH BURNED OUT.SO I REPLACE THE BULBS AND SECURE THE ECM IN ITS LOCATION.. NEXT THING I FIRE IT UP AND HERE COMES A ROUGH IDLE AS WELL AS THE CODE 42 SES LIGHT. I TURN IT OFF AND TURN IT BACK ON HOPING IT WILL FIX ITS SELF AND NOTHING. IT DOES NOT IDEL ROUGH ANYMORE BUT SOMETIMES WILL SURGE (HIGH RPM TO LOW RPM) I DONT KNOW WHERE TO GO FROM HERE. ALSO ME AND MY BUDDY NEVER DISCONECTED THE BYPASS WIRE WHEN SETTING TIMING , COULD THAT BE A MAJOR ISSUE TO CAUSE THIS. BUT LIKE I SAID IT RUNS JUST FINE ONLY THING THAT AT IDLE, COLD START UP IT RUNS AS IF IT WERE ALREADY WITHIN OPERATING TEMP. (LOW RPMS). ANY SUGGESTIONS OR HELP WOULD BE GREATLY APPRECIATED. REMEMBER THIS CODE IS NOT INTERMITTENT. IT WILL COME ON EXACLTLY 2 SECONDS AFTER TRUCK HAS BEEN STARTED. PLEASE HELP...!!!!!!!!!

Cool Zr2 · March 16, 2008

I started reading your post and don't think I'm being a jerk but it is really annoying trying to read a post in caps, especially when its that long. Anyway, welcome!!!!

Cool Zr2 · March 16, 2008

What is code 42 for the W engine, I can find the Z 42 code but not sure if they are the same.

Check your O2 sensor(s) to make sure they aren't burnt on to the exhaust pipe causing it to ground out, that will throw odd codes. One other thing u could try it having a good auto electric shop look it over for shorts, or get a harness from ebay or a junk yard and replace it.

Cool Zr2 · March 16, 2008

From another forum.

Code 42

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It means that one of the wires from the Engine Control Module (ECM) to the ignition module has been broken or cut. It also means that maybe one of the ECM wires to the ignition module has been rubbing off wire insulation on metal and the bare copper wire is touching body or engine metal. It's a simple thing to figure out if you know how to read the ECM wiring diagram, and know how to use an Ohm meter. Maybe you just did some work under the hood, and might have pinched one of the ignition module wires on a bracket or something.