GM 35 IAC Problem Or Idle Error
How to read it
Code 35 reads as 3 flashes, pause, 5 flashes 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 35 mean?
IAC Problem Or Idle Error
Common causes of 35
- Carbon fouled idle air control valve or throttle bore
- Failed IAC motor winding
- Vacuum leak driving idle above target speed
- Damaged IAC wiring or connector
How to fix 35
- Clean the throttle bore and IAC passages with approved cleaner
- Check for vacuum leaks with propane or smoke before replacing parts
- Command idle speed with a scan tool and watch for response
- Test IAC motor resistance per the service manual
- Reset idle learn after cleaning or replacement per the manual
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 35. Include your vehicle, the issue and a source if you have one.