Reductant Injection System Performance
Reductant injection system 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 system that injects diesel exhaust fluid (DEF) into the exhaust stream isn't working right, which can lead to higher emissions.
What the computer is actually seeing
The engine control module monitors the performance of the reductant injection system by checking the amount of DEF injected vs. what is required based on operating conditions.
What a healthy reading looks like
The expected injection rate of DEF should match what's calculated by the engine control unit (ECU) based on engine load and speed.
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; it should be above the minimum mark. If it's low, refill and reset any codes before further testing. Decision: If fluid is low, refill and retest; if not, proceed to next step.
- 22. Inspect the wiring and connectors leading to the reductant injector for damage or corrosion. Repair any issues found. Decision: If wiring is damaged, fix it and retest; if wiring is good, proceed to next step.
- 33. Test the reductant injector operation by measuring its voltage and resistance with a multimeter according to specifications (typically 10-16 volts, resistance around 10-14 ohms). Decision: If test values are outside spec, replace the injector; if within spec, continue diagnosis.
- 44. Check for any blockages in the DEF line leading to the injector. Clear any obstructions found. Decision: If blockage was found and cleared, retest; if no blockage, proceed to the next step.
- 55. Scan for other related fault codes that may indicate problems with the DEF control module or system performance before condemning the injector.
Common causes
- Faulty reductant injector
- Blocked DEF line
- Low DEF fluid level
- Wiring issues to the injector
- Faulty DEF control module
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but driving should be limited as it can lead to increased emissions and potential limp mode.
Will this code come back after clearing it?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this code often accompany other codes?
Because multiple faults in the DEF system can affect overall performance and trigger related codes.
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