What causes GM code 81?

Worn or failed 2-3 shift solenoid Open or shorted shift solenoid wiring Low or dirty transmission fluid Internal transmission mechanical fault

How do I fix GM code 81?

Retrieve codes with a paperclip across ALDL pins A and B and count the Check Engine flashes Check the transmission fluid level and condition Test the shift solenoid and its wiring at the transmission connector Road test and note whether the 2-3 shift is late, harsh or missing Clear codes after the repair and recheck after a road test

81 Transmission 2-3 Shift Error

Q: What does GM code 81 mean?

GM code 81. Transmission 2-3 Shift Error. Applies to 1982-1995 GM cars and C/K trucks with an automatic transmission.

Make: GM (1982-1995)
Category: Powertrain - Transmission
Severity: Check Engine Light
Applies to: 1982-1995 GM cars and C/K trucks with an automatic transmission

How to read it

Code 81 reads as 8 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 81 mean?

81. Transmission 2-3 Shift Error. This code sets when your vehicle computer detects transmission 2-3 shift error.

Common causes of 81

Worn or failed 2-3 shift solenoid
Open or shorted shift solenoid wiring
Low or dirty transmission fluid
Internal transmission mechanical fault

How to fix 81

Retrieve codes with a paperclip across ALDL pins A and B and count the Check Engine flashes
Check the transmission fluid level and condition
Test the shift solenoid and its wiring at the transmission connector
Road test and note whether the 2-3 shift is late, harsh or missing
Clear codes after the repair and recheck after a road test