58 Trans Fluid Temp Sensor Circuit Low Voltage

How to read it

Code 58 reads as 5 flashes, pause, 8 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 58 mean?

58 — Trans Fluid Temp Sensor Circuit Low Voltage. This code sets when your vehicle computer detects trans fluid temp sensor circuit low voltage.

Common causes of 58

• Shorted trans fluid temp sensor or wiring
• Sensor wiring shorted to ground inside the trans
• Failed temp sensor in the valve body harness
• Faulty ECM temp input

How to fix 58

1. Read codes with a paperclip jumper or an ALDL scan tool
2. Check trans fluid level and condition first
3. Unplug the trans connector and watch the temp reading change
4. Test sensor resistance and compare hot against cold
5. Repair wiring or replace the internal harness and sensor
6. Refill with correct fluid and retest