72 Vehicle Speed Sensor Signal Circuit Error

How to read it

Code 72 reads as 7 flashes, pause, 2 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 72 mean?

72. Vehicle Speed Sensor Signal Circuit Error. This code sets when your vehicle computer detects vehicle speed sensor signal circuit error.

Common causes of 72

• Failed vehicle speed sensor
• Damaged speedometer cable or drive gear where fitted
• Broken VSS wiring or buffer module fault
• Corroded connector at the trans

How to fix 72

1. Read codes with a paperclip jumper and note if the speedometer drops out
2. Inspect the VSS connector at the transmission
3. Check wiring from the sensor to the buffer and ECM
4. Test sensor output while the wheels turn
5. Replace the sensor or drive gear as tests show
6. Road test and confirm speed reads steady