SCR Catalyst Temperature Too High
The SCR catalyst temperature is exceeding the normal range.
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)
The system is showing that the temperature of the SCR catalytic converter is too high, which can lead to damage if not addressed quickly.
What the computer is actually seeing
The Engine Control Module (ECM) reads a temperature signal from the SCR temperature sensor, typically around 800-900°F during normal operation. If the signal exceeds 1,150°F, the code sets.
What a healthy reading looks like
During normal operation, SCR catalyst temperatures should be between 800°F and 1,000°F. A reading above 1,150°F triggers the fault code.
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 wiring and connectors at the SCR temperature sensor for damage or corrosion. If damaged, repair/replace the wiring or connector.
- 22. Measure the SCR temperature sensor output with a scan tool or multimeter while the engine is running. If it reads below 800°F or above 1,150°F, continue to step 3; if it's within range, the sensor may be faulty.
- 33. Check for any visible exhaust leaks or blockages in the SCR system. Repair any leaks or clear any blockages found.
- 44. Verify DEF (Diesel Exhaust Fluid) quality and level. Poor quality or low DEF can cause high SCR temperatures—refill or replace as needed.
- 55. Inspect the turbocharger operation. Use a boost gauge to confirm it's functioning correctly. If it's not producing proper boost, consider rebuilding/replacing the turbo.
Common causes
- Faulty SCR temperature sensor
- Exhaust system blockage
- Fuel quality issues leading to inefficient combustion
- Insufficient DEF flow
- Failed turbocharger causing excessive exhaust temperatures
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not safe to drive as high temperatures can damage the SCR system leading to costly repairs.
Will the code come back after clearing?
Yes, if the underlying issue is not fixed, the code will likely return.
Why does this code often come with an engine performance issue?
High SCR temperatures can indicate incomplete combustion or exhaust system faults, which can affect overall engine performance.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →