Exhaust Gas Temperature Sensor 3
Indicates a fault with the exhaust gas temperature sensor 3.
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What it means (plain English)
The computer is saying there's a problem with the temperature sensor that measures how hot the exhaust gases are coming out of the engine.
What the computer is actually seeing
The ECM is monitoring the voltage from the exhaust gas temperature (EGT) sensor 3, which should typically range from 0.5V to 4.5V depending on the exhaust temperature. If it sees a value outside of this range or detects a circuit fault, it triggers the SPN 5466 code.
What a healthy reading looks like
Normal operation of EGT sensors typically shows voltages between 0.5V (around 300°F / 150°C) and 4.5V (around 1800°F / 1000°C).
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 connector for EGT sensor 3 for any visible damage or corrosion. Repair as necessary.
- 22. Check the exhaust gas temperature sensor 3 voltage at the ECM while the engine is running. It should be between 0.5V and 4.5V. If not, proceed to the next step.
- 33. Disconnect the sensor and check for continuity in the wiring harness leading to the ECM. If there's no continuity, repair the wiring.
- 44. If the wiring is intact, replace the exhaust gas temperature sensor 3 and retest the system.
- 55. If the code returns after replacing the sensor, consider testing or reprogramming the ECM.
Common causes
- Failed exhaust gas temperature sensor 3
- Wiring damage or poor connection in the sensor circuit
- Faulty engine control module (ECM)
- Excessive exhaust backpressure affecting the sensor
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable, but you may see reduced engine performance and increased emissions. Fix it soon.
Will this code come back after reset?
If the issue persists, yes. Fix the underlying cause to prevent it from returning.
Why does this code appear with other SPN codes?
It often pairs with other EGT sensor codes due to similar wiring and sensor circuit issues.
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