What causes GM code 15?

Open coolant temp sensor or unplugged connector Broken signal wire or corroded ECM connector pin Failed sensor reading far below actual temperature Stuck open thermostat keeping the engine cold on some models

How do I fix GM code 15?

Inspect the sensor connector and wiring for opens and green corrosion Jumper the sensor harness and check whether the scan reading swings hot to prove the circuit Measure sensor resistance and compare to the factory temperature chart Replace a thermostat stuck open if warm up takes too long Clear the code and verify closed loop fuel control returns

15 Engine Coolant Temp Sensor Error Low Temp Indicated

Q: What does GM code 15 mean?

GM code 15. Engine Coolant Temp Sensor Error Low Temp Indicated. Applies to 1982-1995 GM cars and C/K trucks, Camaro, Corvette.

Make: GM (1982-1995)
Category: Powertrain - Fuel/Air Metering
Severity: Check Engine Light
Applies to: 1982-1995 GM cars and C/K trucks, Camaro, Corvette

How to read it

Code 15 reads as 1 flash, 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.

What does GM code 15 mean?

15. Engine Coolant Temp Sensor Error Low Temp Indicated. This code sets when your vehicle computer detects engine coolant temp sensor error low temp indicated.

Common causes of 15

Open coolant temp sensor or unplugged connector
Broken signal wire or corroded ECM connector pin
Failed sensor reading far below actual temperature
Stuck open thermostat keeping the engine cold on some models

How to fix 15

Inspect the sensor connector and wiring for opens and green corrosion
Jumper the sensor harness and check whether the scan reading swings hot to prove the circuit
Measure sensor resistance and compare to the factory temperature chart
Replace a thermostat stuck open if warm up takes too long
Clear the code and verify closed loop fuel control returns