Engine Exhaust Temperature Sensor Fault
This code indicates an issue with the exhaust temperature sensor reading.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
Your truck's computer is getting weird temperature readings from the exhaust temperature sensor, which could affect engine performance and emissions compliance.
What the computer is actually seeing
The engine control module (ECM) calculates exhaust temperature based on input from the exhaust temperature sensor, expecting a range of approximately 300°F to 900°F (150°C to 480°C) when the engine is running.
What a healthy reading looks like
Normal temp readings should range from 300°F to 900°F (150°C to 480°C) during operation.
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.
- 1Check the exhaust temperature sensor wiring for damage or wear.
- 2Inspect the sensor connector for corrosion or improper fit.
- 3Test the exhaust temperature sensor resistance: at room temperature, it should read around 2,000 to 2,500 ohms.
- 4Start the engine and monitor exhaust temperature with a scan tool; it should display a reasonable range (300°F to 900°F) based on engine operation.
- 5If readings are abnormal or the sensor is unresponsive, replace the exhaust temperature sensor.
Common causes
- Faulty exhaust temperature sensor
- Wiring issues, such as short or open circuits
- Connector problems or corrosion
- Extreme exhaust system temperatures
- ECM software issues
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s moderate; you can drive cautiously but fix it soon to avoid further issues.
Will this code come back after I clear it?
It may come back if the underlying issue isn't resolved, like a faulty sensor or wiring.
Why does this code pair with SPN 1998?
SPN 1998 is another temperature sensor fault that often triggers alongside SPN 1999 in diesel systems.
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