Reductant Heater A Performance
The reductant heater is not performing as expected.
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 engine computer activates a heater to warm up the diesel exhaust fluid (DEF) before spraying it into the exhaust stream. If that heater doesn't warm up properly or has a problem, it triggers this code.
What the computer is actually seeing
The vehicle's computer monitors the voltage and current draw of the reductant heater. Typically, it expects a steady current draw indicating proper operation. If it notices an abnormal reading, like too low or too high, it will trigger this fault code.
What a healthy reading looks like
The expected current draw should be between 10 to 15 amps when the heater is operating; anything lower than 8 amps or higher than 17 amps may set the 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. Check the DEF fluid level; ensure it's above the minimum level required.
- 22. Inspect the wiring and connectors for the reductant heater for any damage or corrosion.
- 33. Measure the current draw of the reductant heater during operation; it should be between 10 to 15 amps. If outside this range, proceed to the next step.
- 44. Test the resistance of the reductant heater; it should be within specs (typically around 5 to 20 ohms). If not, replace the heater.
- 55. If the heater tests good, check the engine control module (ECM) for fault codes and possible updates.
Common causes
- Faulty reductant heater
- Bad wiring or connector to the heater
- Defective engine control module (ECM)
- Faulty temperature sensor
- Insufficient DEF fluid level
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to avoid driving long distances until the issue is resolved, as it can affect emissions system performance.
Will the code come back after clearing it?
If the underlying issue isn't fixed, the code will likely return after a short time.
Why does this code pair with other codes?
Multiple codes can be set if there are issues with the emissions system, as many components are interconnected.
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