Exhaust Temperature Sensor 1 Circuit High
The exhaust temperature sensor circuit is reporting a high voltage.
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What it means (plain English)
The computer sees a voltage higher than 4.9 volts from the exhaust temperature sensor, which usually means there's a short or the sensor is faulty.
What the computer is actually seeing
The ECM expects a voltage from the exhaust temperature sensor to be between 0.5 to 4.5 volts. A reading above 4.9 volts triggers this fault code.
What a healthy reading looks like
0.5 to 4.5 volts from the exhaust temperature sensor under normal operating conditions.
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 wiring and connectors for the exhaust temperature sensor. Look for fraying, disconnection, or corrosion. Fix any issues found.
- 22. Test the voltage at the exhaust temperature sensor connector with the key on and engine off. You should see between 0.5 and 4.5 volts. If it's over 4.9 volts, go to step 3.
- 33. Check for shorts in the wiring harness to the sensor. Disconnect the sensor and measure resistance on the harness wire back to the ECM. Should be near 0 ohms, replace any bad wiring.
- 44. If wiring is good, replace the exhaust temperature sensor and clear the code. Then, retest for code reappearance.
Common causes
- Faulty exhaust temperature sensor
- Short circuit in wiring harness
- Poor connection at the sensor or ECM
- Corroded connectors
- Exhaust system leaks affecting sensor readings
Typical repair cost
$$$
Related codes
Frequently asked questions
Can I drive with this code active?
Yes, but you should not ignore it as it can lead to engine performance issues and higher emissions.
Will this code come back after clearing?
It can if the underlying issue isn't resolved.
Why does this code pair with other SPN codes?
SPN codes often indicate related issues in the same system; for example, multiple sensors monitoring exhaust may trigger at the same time.
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