Engine Exhaust Gas Temperature Sensor 1
The ECM detects a fault with the exhaust gas temperature sensor 1.
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What it means (plain English)
The engine computer is getting bad readings from the exhaust gas temperature sensor, which checks how hot the exhaust gases are after combustion.
What the computer is actually seeing
The ECM expects a signal voltage between 0.2V (cold exhaust) and 4.5V (hot exhaust). If the voltage is out of this range or missing, a fault code is triggered.
What a healthy reading looks like
Normal operation should see a temperature around 300°C to 900°C (572°F to 1652°F) corresponding to around 1V to 3V output from the sensor.
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 condition of the wiring and connectors at the exhaust gas temperature sensor. Look for frays or corrosion.
- 2 - If wiring/connections are fine, proceed to Step 2.
- 32. Measure the voltage at the exhaust gas temperature sensor with the engine running. Expected voltage: 1V-3V (temperature range 300°C-900°C).
- 4 - If voltage is within range, suspect an ECM issue.
- 5 - If voltage is out of range or missing, proceed to Step 3.
- 63. Check the exhaust gas temperature sensor by replacing it with a known good one or testing it with a multimeter according to manufacturer specifications.
- 7 - If the code clears after replacement, sensor was faulty. If not, suspect an ECM issue.
Common causes
- Wiring issues (shorts, opens, corrosion) in the EGT sensor circuit
- Failed exhaust gas temperature sensor
- Faulty Engine Control Module (ECM)
- Exhaust leaks affecting sensor readings
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable but monitor for performance issues; fix soon to avoid further damage.
Will this code come back after clearing?
If the problem isn't fixed, it will return after driving for a while.
Why does this code sometimes pair with SPN 1517?
SPN 1517 indicates a similar issue with the second exhaust gas temperature sensor, showing that both sensors can experience faults due to wiring or ECM issues.
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