Exhaust Aftertreatment Fuel Injector Circuit Intermittent (Generic)
The P4059 code means the vehicle's onboard diagnostic system has detected: Exhaust Aftertreatment Fuel Injector Circuit Intermittent (Generic). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $600 (parts and labor)
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Common Symptoms
- Check Engine Light intermittent
- Sporadic DPF regen failures
- Inconsistent regen performance
- Occasional exhaust smell
Probable Causes (Ranked by Likelihood)
- Loose aftertreatment injector connector Very High
- Wiring heat damage causing intermittent contact High
- Injector sticking intermittently Moderate
- PCM driver intermittent Low
Step-by-Step Diagnostic Procedure
-
Wiggle test injector connector while monitoring operation
-
Inspect wiring for heat damage near exhaust
-
Command active regen and monitor injector operation
-
Check connector locking mechanism
Frequently Asked Questions
Why does the aftertreatment injector have intermittent issues?
The injector is mounted on the exhaust system in an extremely hot environment.
Can intermittent regen failures clog the DPF?
Yes, each failed regeneration means soot is not burned off.
Can I drive with P4059?
You can drive short distances but schedule a repair promptly.
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