Common questions

What does the Code 42 on a GM car mean?

What does the Code 42 on a GM car mean?

Trouble Codes› GM OBD Trouble Codes› GM Code 42 CODE 42 – Electronic Spark Timing or Bypass Fault 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.

What are the causes of a GM code 42 spark fault?

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 Return to Chart

Why does my engine have trouble 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.

What does code 42 mean in electrical spark timing?

Code 42 sets if there is an open, or a short to ground, in the EST or by-pass circuit. DIAGNOSTIC CHARTS > CODE 42 – ELECTRONIC SPARK TIMING > TEST DESCRIPTION. NOTE: Test numbers refer to test numbers on diagnostic chart. 1. Code 42 means the ECM has seen an open, or short to ground, in EST or by-pass circuit.

Trouble Codes› GM OBD Trouble Codes› GM Code 42 CODE 42 – Electronic Spark Timing or Bypass Fault 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.

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 Return to Chart

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.

What are the conditions for setting code 42?

The conditions for setting code 42 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 43 include: 1) BYPASS line is open or grounded 2) EST line is open or grounded

Where is the code on a Chevy Astro?

You will notice the code is located on the front of the tube on the passengers side of the van. However, I have found that on 1988 and older, the code is found on the front of the drivers side axle tube. NOTE! The first 3 letters of the code stamp are the ones that matter.

What is the RPO code on a 1989 Astro van?

CLICK ABOVE TO SEE A RPO STICKER FROM A 1989 ASTRO/SAFARI VAN RPO AXLE CODE LIST BELOW: GU2 2:73 ratio GU43:08 ratio GU53:23 ratio GU63:42 ratio GT43:73 ratio GT54:10 ratio GQ1Open Differential Rear Axle G80GOV-LOC Rear Axle NOTE! The RPO CODE on the sticker only shows which rear axle was installed at the factory.

Where is the Axle code on an Astro van?

You will need to clean off the axle tube well to see the letters-numbers clearly. You will notice the code is located on the front of the tube on the passengers side of the van. However, I have found that on 1988 and older, the code is found on the front of the drivers side axle tube.

What causes a GM engine to set code 42?

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.

Where can I find a 1994 Astro van?

1994 chevrolet astro cargo – gig harbor, wahunt street autogig harbor, wa 98335ph: 2534050240web: www. It has cloth seats (blue) with no tears or wear marks.

What happens when you set a code 42?

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 code 42 are:

What does trouble code 42 mean on spark timing?

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

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Ruth Doyle