GM 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.
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 72 mean?
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
- Read codes with a paperclip jumper and note if the speedometer drops out
- Inspect the VSS connector at the transmission
- Check wiring from the sensor to the buffer and ECM
- Test sensor output while the wheels turn
- Replace the sensor or drive gear as tests show
- Road test and confirm speed reads steady
Source
Qualified source review
Sources and review
Review: qualified. Read the source limits below.
- GM and Chevrolet OBD1 Trouble Codes (ALDL Fault Code List)
live reference page (troublecodes.net)
Supports: code identity and GM meaning
Fetched directly. Single publisher, so the record is qualified, not verified. Causes and check order are curator-written from the circuit the code names.
https://www.troublecodes.net/gm/
Last updated 2026-09-19.
Report a correction for 72. Include your vehicle, the issue and a source if you have one.