Reductant Injection System Performance
The system is not injecting the correct amount of reductant (usually urea) into the exhaust stream.
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What it means (plain English)
The engine's computer can't get the right amount of urea into the exhaust system to reduce emissions properly.
What the computer is actually seeing
The engine control module (ECM) monitors the reductant injection system's flow rate, temperature, and pressure. If the system doesn't inject the expected amount of urea when commanded, it triggers this code.
What a healthy reading looks like
Expected flow rate for urea injection is typically around 1.0 to 3.0 liters per hour, depending on engine load and conditions. Reductant temperature must be between -11°C to 35°C (12°F to 95°F).
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 urea fluid level in the tank. Ensure it is at least 1/4 full. If low, refill and clear the code. Decision Point: If the code returns, proceed to step 2. If not, issue resolved.
- 22. Inspect the urea injector for blockage or damage. Clean or replace as necessary. Decision Point: If the injector was dirty and you cleaned it, retest. If code returns, proceed to step 3.
- 33. Test the urea pressure sensor using a multimeter. Expected values are usually between 0.5V (low flow) to 4.5V (high flow). If readings are out of range, replace the sensor. Decision Point: If readings are okay, move to step 4.
- 44. Inspect wiring and connectors for signs of wear or damage, specifically at the injector and sensor. Repair any issues found. Decision Point: If no issues found, consider replacing the PCM.
Common causes
- Low urea fluid level
- Clogged or malfunctioning injector
- Faulty pressure sensor
- Damaged wiring or connectors
- Contaminated urea
Typical repair cost
$$$
Related codes
Frequently asked questions
Can I still drive my vehicle with this code?
Yes, but emissions may be impacted, and you might experience reduced power or efficiency.
Will this code come back after I clear it?
It may come back if the underlying issue isn’t fixed; monitor the system after repairs.
Why am I seeing this code together with other codes?
The reductant system issues can cause multiple codes since they all relate to emissions control.
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