What causes GM code 43?

Failed knock sensor Broken or shorted knock sensor wire Loose sensor or wrong torque changing its signal Excessive engine noise from mechanical wear tripping detection

How do I fix GM code 43?

Inspect the knock sensor wire for cracks and grounding against the block Verify the sensor is torqued to specification Tap near the sensor with the engine running and watch for timing retard on a scan tool Test sensor and ESC module circuits per the manual Repair wiring before replacing the sensor

43 Knock Sensor Error

Q: What does GM code 43 mean?

GM code 43 — Knock Sensor Error. Applies to 1982-1995 GM cars and C/K trucks, Camaro, Corvette.

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

How to read it

Code 43 reads as 4 flashes, pause, 3 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 43 mean?

43 — Knock Sensor Error. This code sets when your vehicle computer detects knock sensor error.

Common causes of 43

Failed knock sensor
Broken or shorted knock sensor wire
Loose sensor or wrong torque changing its signal
Excessive engine noise from mechanical wear tripping detection

How to fix 43

Inspect the knock sensor wire for cracks and grounding against the block
Verify the sensor is torqued to specification
Tap near the sensor with the engine running and watch for timing retard on a scan tool
Test sensor and ESC module circuits per the manual
Repair wiring before replacing the sensor