Engine Exhaust Temperature Sensor Circuit Low
Engine exhaust temperature sensor is reporting low voltage.
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What it means (plain English)
The exhaust temperature sensor is sending a voltage reading that's too low, typically below 0.5 volts, indicating a possible wiring issue or a faulty sensor.
What the computer is actually seeing
The engine control unit (ECU) expects the exhaust temperature sensor to provide a voltage signal between 0.5 to 4.5 volts depending on the exhaust temperature. If it's below 0.5 volts for an extended period, a fault code is triggered.
What a healthy reading looks like
Normal exhaust temperature sensor voltage should be between 0.5 to 4.5 volts; under 0.5 volts indicates a problem.
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 connectors for damage or corrosion. If damaged, repair or replace as necessary. Decision: If repairs fix the issue, clear the code and retest.
- 22. Measure the voltage at the exhaust temperature sensor connector with the engine running. Check if it reads below 0.5 volts. Decision: If below, proceed to step 3. If normal, replace the sensor.
- 33. Disconnect the exhaust temperature sensor and measure the resistance across the terminals with a multimeter. Expect a certain range based on OEM specs (typically 1000-2000 ohms). Decision: If out of range, replace the sensor. If in range, check wiring to the ECU.
- 44. Inspect for potential shorts in the wiring harness by wiggling the wires while monitoring the voltage. If the voltage changes, there's a wiring issue. Decision: Repair the wiring as necessary.
Common causes
- Faulty exhaust temperature sensor
- Wiring issues or short to ground
- Corroded connectors
- Open circuit in sensor wiring
- Exhaust leaks affecting sensor readings
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with this code present?
It's best to get this fixed soon, as it can affect engine performance and emissions.
Will this code return after I clear it?
If the underlying issue isn't fixed, yes, this code is likely to return.
Why do I see this code alongside SPN 3555?
These codes often occur together because they relate to the same exhaust temperature sensor circuit.
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