Check engine code 42?

1995 CHEVROLET SILVERADO
255,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
Avatar
LMONTE007
  • MEMBER
  • 2 POSTS
A few weeks before the engine light came on, I heard some sort of exhaust issue or something happening. I have attempted to patch a hole in the muffler. After the code came on and the first couple of days it would die while stopped and then that stopped. Now when I drive the engine is puttering, and when you push the gas, there is a hesitation, but the truck has not been dying. The check engine light seems to be illuminating at different brightness. The truck starts normally. The book that comes with OBD one reader says that it’s either 1- electronic spark timing, circuit open or shorted or 2-direct ignition system bypass circuit open or shorted to ground during Engine run or 3- fuel cut off relay circuit open or shorted to ground. Any advice on how or what to test?
Nov 21, 2024 at 1:46 PM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
So this codes is telling you the timing bypass is disconnected, can you check it? Here is the location.

The Code 42 indicates a problem with the Electronic Spark Timing (EST) circuit it refers to a "EST Bypass Circuit - Open or Grounded"

This is a single wire sealed connector that has a tan with black stripe lead. This connector breaks out of the wiring harness below the heater case in the passenger compartment.
Dec 4, 2024 at 10:50 AM
Avatar
LMONTE007
  • MEMBER
  • 2 POSTS
Hello, I am familiar with that wire and I have disconnected it and connected it again.
Dec 4, 2024 at 12:41 PM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
Okay, I have seen the ignition module or ignition coil start to go bad and cause this issue. Here is how to change them out which should fix the problem, disconnect the battery to clear the codes after the repair is completed. Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.
Dec 5, 2024 at 12:58 PM