OBD-I Codes List

GM 61 A/C System Performance Fault

Make
GM (1982-1995)
Category
Powertrain - Computer and Auxiliary Controls
Severity
Check Engine Light

How to read it

Code 61 reads as 6 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 61 mean?

A/C System Performance Fault

Common causes of 61

  • Low refrigerant charge
  • Weak A/C compressor or slipping belt
  • Faulty A/C pressure sensor signal
  • Engine running hot or cooling fan fault

How to fix 61

  1. Read codes with an ALDL scan tool and note engine temp
  2. Check belt condition and tension
  3. Check refrigerant pressure with gauges
  4. Verify the cooling fan runs when the A/C is on
  5. Test the pressure sensor signal against gauge pressure
  6. Fix the root cause, clear the code and retest A/C on

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 61. Include your vehicle, the issue and a source if you have one.

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