OBD-I Trouble Code Lookup

Search 68 pre-1996 diagnostic trouble codes for what they mean, what causes them, and how to fix them. No scanner needed — just a paperclip.

How to read OBD-I codes

  1. Find the connector. Under the dash, driver side. GM calls it ALDL. Ford hides a test connector under the hood.
  2. Jump it. GM: paperclip across terminals A and B, key off first. Ford: jumper the STI connector and run the KOEO self-test.
  3. Key on, engine off. Count the check-engine flashes. Long pause separates codes. Code 12 on a GM means the system is ready.
  4. Look it up. Enter the number above. Then diagnose before you spend.

GM (1982-1995)

Paperclip codes. Jump terminals A and B on the ALDL connector, count the flashes. 68 codes.

Ford

Coming soon. The Ford code list is in the works — check back.

Chrysler

Coming soon. The Chrysler code list is in the works — check back.

Toyota

Coming soon. The Toyota code list is in the works — check back.

Honda

Coming soon. The Honda code list is in the works — check back.

What is OBD-I Codes List?

OBD-I Codes List is a free, no-sign-up lookup for pre-1996 trouble codes. Every page explains what the code means, what usually causes it, and the order of steps to check and fix it. Written for DIYers with no factory service manual. One make at a time, starting with GM.

Popular GM codes