DEF Dosing Valve Circuit Open (Generic)
The P4060 code means the vehicle's onboard diagnostic system has detected: DEF Dosing Valve Circuit Open (Generic). This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $200 - $700 (parts and labor)
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Common Symptoms
- Check Engine Light on
- DEF system fault warning
- SCR catalyst not receiving DEF
- Speed derate countdown active
- Emissions non-compliance
Probable Causes (Ranked by Likelihood)
- Open circuit in DEF dosing valve wiring Very High
- Failed DEF dosing valve solenoid High
- Connector damage from chemical exposure Moderate
- PCM DEF driver failure Low
Step-by-Step Diagnostic Procedure
-
Check DEF dosing valve connector and wiring
-
Test dosing valve solenoid resistance
-
Inspect connector for DEF crystal contamination
-
Verify PCM driver signal output
Frequently Asked Questions
What is a DEF dosing valve?
The DEF dosing valve controls the injection of diesel exhaust fluid into the exhaust stream upstream of the SCR catalyst.
Can I drive with P4060?
No, most vehicles will start a speed derate countdown timer.
How much is a DEF dosing valve?
The valve costs $150-400. With labor, expect $300-700 total.
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