Exhaust Gas Temperature (EGT) Sensor 1 Circuit High
The exhaust gas temperature sensor is reporting a voltage that is higher than expected.
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What it means (plain English)
The EGT sensor measures how hot the exhaust gases are; if it sends back a signal that's too high, the computer thinks something's wrong.
What the computer is actually seeing
The engine control module (ECM) sees a voltage from the EGT sensor that exceeds the normal range, usually over 4.5 volts.
What a healthy reading looks like
EGT sensor should output between 0.5V to 3.5V when exhaust temp is within normal operating range.
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.
- 1Verify the fault code with a scan tool and check for additional codes.
- 2Visually inspect the wiring and connectors for damage or corrosion (look for frayed wires or loose connections).
- 3Check the voltage at the EGT sensor while the engine is running; it should be between 0.5V and 3.5V. If it's above this range, the sensor or wiring may be faulty.
- 4Disconnect the EGT sensor and check for any shorts to voltage in the wiring harness (should not have continuity to a power source).
- 5If the wiring is fine, replace the EGT sensor and clear the fault codes, then test drive the vehicle to see if the code returns.
Common causes
- Damaged EGT sensor
- Wiring issues (short to voltage)
- Faulty ECM
- Poor ground connection
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you should fix it soon, but the vehicle is usually drivable. Watch for performance issues.
Will this code come back after repairs?
If you fix the underlying issue (sensor or wiring), the code should not return.
Why does this code show up with another code like SPN 1559?
Multiple codes often indicate related issues; in this case, both may stem from a failing EGT sensor.
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