GM 41 Ignition Control Error
How to read it
Code 41 reads as 4 flashes, pause, 1 flash on the check-engine light. Jump terminals A and B on the ALDL connector with the key off, then turn the key on with the engine off and count the check-engine flashes.
New to flash codes? The How to Read GM OBD-I Codes with a Paperclip walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does GM code 41 mean?
Ignition Control Error
Common causes of 41
- Failed ignition module
- Open or shorted bypass or EST wiring
- Poor module ground
- On some models an incorrect MEM CAL module sets this code
How to fix 41
- Check for spark at the plugs to confirm the failure
- Inspect module connectors for heat damage and corrosion
- Test bypass and EST circuits per the service manual
- Verify correct MEM CAL installation on serviced ECMs
- Replace the module only after wiring and grounds test good
Source
Qualified source review
Sources and review
Review: qualified. Read the source limits below.
- GM and Chevrolet OBD1 Trouble Codes (ALDL Fault Code List)
live reference page (troublecodes.net)
Supports: code identity and GM meaning
Fetched directly. Single publisher, so the record is qualified, not verified. Causes and check order are curator-written from the circuit the code names.
https://www.troublecodes.net/gm/
Last updated 2026-09-19.
Report a correction for 41. Include your vehicle, the issue and a source if you have one.