Engine Exhaust Temperature Sensor Circuit High
Indicates a high voltage reading from the exhaust temperature sensor.
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What it means (plain English)
The exhaust temperature sensor is detecting a voltage that's too high, suggesting a possible short in the wiring or sensor failure. Usually, it should read between 0.5V and 4.5V based on exhaust temperatures.
What the computer is actually seeing
The ECM is seeing an exhaust temperature sensor voltage reading above the normal range—typically greater than 4.5V.
What a healthy reading looks like
Expect voltage readings from the exhaust temperature sensor between 0.5V and 4.5V under normal operation. A reading over 4.5V indicates a fault.
Guided diagnostic — the DiagCoach way
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.
- 11. Inspect the exhaust temperature sensor wiring and connector for damage or corrosion. Repair or replace as necessary. Decision Point: If wiring is damaged, fix it. If not, proceed.
- 22. Measure the voltage at the sensor while the engine is running. You should see a value between 0.5V and 4.5V. Decision Point: If voltage is above 4.5V, replace the sensor. If not, continue.
- 33. Check for continuity in the wiring between the ECM and the exhaust temperature sensor. Decision Point: If there's an open circuit, repair the wiring. If continuity is good, go to the next step.
- 44. Clear the code and perform a road test to see if it returns. Decision Point: If code comes back, consider replacing the exhaust temperature sensor.
Common causes
- Wiring short to power or ground
- Faulty exhaust temperature sensor
- Corrosion or damaged connectors
- Open circuit in the sensor circuit
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's advisable to fix it soon, as it may cause issues with exhaust regulations and performance.
Will this issue come back if I clear the code?
If the underlying problem isn't fixed, the code is likely to return.
Why am I also seeing SPN 3931 with this code?
SPN 3931 indicates a related fault with the exhaust temperature sensor circuit, often seen alongside SPN 3930.
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