Engine Exhaust Temperature Sensor Circuit High

The exhaust temperature sensor measures how hot the exhaust gases are coming out of the engine. When it reports a high temp, it can mean there's an issue with the sensor or the exhaust system causing excess heat.

The engine control module (ECM) sees a voltage reading from the exhaust temperature sensor above its normal operating range, typically over 1.5 volts when it should be around 0.5 to 1.3 volts during normal operation.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check the exhaust temperature sensor wiring and connectors for damage or corrosion. If there are issues, repair the wiring and clear the code. Decision point: If repair does not resolve, continue to step 2.
2. 22. Measure the voltage at the exhaust temperature sensor connector. Ensure it is between 0.5 and 1.3 volts at idle. Decision point: If the voltage is normal, suspect a faulty sensor; if high, move to step 3.
3. 33. Inspect the exhaust system for blockages or restrictions. Check for carbon buildup, broken components, or signs of excessive heat. Decision point: If found, repair the exhaust system; if not, proceed to step 4.
4. 44. Replace the exhaust temperature sensor and clear the code. Decision point: If code returns, check ECM for faults.

• Faulty exhaust temperature sensor
• Wiring issues such as shorts or open circuits
• Exhaust system blockages causing excessive heat
• Corrosion on connectors affecting signal
• Faulty ECM

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