Reductant Injector Circuit Range/Performance Problem

The system that sprays diesel exhaust fluid (DEF) is not working properly, possibly too little or too much fluid is injected into the exhaust to reduce emissions.

The engine control module (ECM) monitors the reductant injector circuit for voltage and performance. If the voltage does not match expected levels or the flow rate of the DEF is out of range, it triggers this code.

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.

1. 11. Inspect the wiring and connectors to the reductant injector for damage or corrosion. If found, repair or replace as necessary. Decision Point: If wiring is good, continue to next step. If not, fix wiring and retest.
2. 22. Check the voltage at the reductant injector connector with the engine running. You should see around 12V. Decision Point: If voltage is within spec, proceed. If not, suspect wiring or ECM issues.
3. 33. Test the flow rate of the DEF through the injector. Use a flow meter if necessary to ensure it matches specifications. Decision Point: If flow rate is normal, injector is likely okay. If it's low or blocked, clean or replace the injector as needed.
4. 44. Check the DEF tank for contamination or incorrect fluid type. Ensure the DEF concentration is between 32.5% and 33.5%. Decision Point: If DEF is contaminated, drain and refill with correct fluid. Retest the system.

• Faulty reductant injector
• Wiring issues in the reductant circuit
• Faulty ECM
• Incorrect DEF concentration
• Blockage in the injector nozzle

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