PCM/ECM/TCM Internal Temperature Sensor Circuit

What You Might Notice

• Check engine light illuminated
• Engine will not start
• Engine may stall
• Improper shifting
• Transmission warning lamp illuminated

Most Common Causes

1. 1

   Corroded/Damaged Connector

   Corrosion or physical damage to temperature sensor connector prevents proper signal transmission.

2. 2

   Faulty Wiring

   Damaged or broken wires in the temperature sensor circuit disrupt electrical connection.

3. 3

   Loose Ground Strap

   Defective or loose control module ground connection causes erratic sensor readings.

4. 4

   Defective PCM/ECM/TCM

   Failed powertrain control module cannot properly process temperature sensor signals.

How to Diagnose It

1. 1

   Check Corroded/Damaged Connector — Corrosion or physical damage to temperature sensor connector prevents proper signal transmission.

2. 2

   Check Faulty Wiring — Damaged or broken wires in the temperature sensor circuit disrupt electrical connection.

3. 3

   Check Loose Ground Strap — Defective or loose control module ground connection causes erratic sensor readings.

4. 4

   Check Defective PCM/ECM/TCM — Failed powertrain control module cannot properly process temperature sensor signals.

How to Fix It

1. 1

   Inspect Connector

   Clean and verify connector integrity for corrosion or damage.

   Connector↗
2. 2

   Check Wiring

   Inspect all sensor circuit wiring for breaks, cuts, or corrosion.

   Wiring Harness↗
3. 3

   Verify Ground Strap

   Test and tighten control module ground connection.

   Ground Strap↗
4. 4

   Replace Temperature Sensor

   Replace temperature sensor if circuit connections are verified good.

   Temperature Sensor↗