Reductant Injector Circuit High
The control module is detecting a high voltage in the reductant injector circuit.
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What it means (plain English)
Inside the engine control module, an electrical signal from the reductant injector is reading higher than 4.5 volts, which usually indicates a short in the wiring or the injector itself.
What the computer is actually seeing
The ECM sees a voltage reading above the defined threshold, typically higher than 4.5 volts, which suggests an electrical issue with the reductant injector circuit.
What a healthy reading looks like
The electrical reference voltage should be between 0.5 and 2.5 volts when the injector is off. During operation, you should see pulsed signals maintaining below 4.5 volts.
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 the wiring harness and connectors for visible damage or corrosion near the reductant injector.
- 22. Check the voltage at the injector connector with a multimeter. A proper reading should be within 0.5 to 2.5 volts when the injector is off.
- 33. If high voltage is detected, disconnect the connector and recheck the voltage. If it drops back to normal, the injector is faulty. If still high, continue.
- 44. Inspect the injector wiring for short circuits by performing a continuity test to ground. Repair any shorts found.
- 55. Clear the code and retest the system. If the code returns, suspect a faulty ECM.
Common causes
- Short to power in the injector wiring
- Faulty reductant injector
- Connector corrosion or damage
- Failed engine control module (ECM)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive long-term with this code; it can lead to DPF issues and increased emissions.
Will this code come back after I clear it?
If the underlying issue isn't fixed, yes, it will likely come back.
Why might this code pair with other codes?
These codes often indicate related issues in the SCR or emissions system, commonly seen when there's a failure in injector performance.
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