DEF Pump Circuit High (Generic)
The P4068 code means the vehicle's onboard diagnostic system has detected: DEF Pump Circuit High (Generic). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $300 - $900 (parts and labor)
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Common Symptoms
- Check Engine Light on
- DEF pump running at high current
- Potential DEF overpressure
- DEF line or injector damage risk
- System warning
Probable Causes (Ranked by Likelihood)
- Short to voltage in pump circuit Very High
- DEF line restriction causing pump overwork High
- Frozen DEF causing high back pressure Moderate
- Pump motor winding fault Low
Step-by-Step Diagnostic Procedure
-
Check DEF pump current draw
-
Inspect DEF lines for restrictions or kinks
-
Verify DEF pressure at injector
-
Test pump motor for winding shorts
Frequently Asked Questions
Can a restricted DEF line cause pump failure?
Yes, a kinked, frozen, or crystallized DEF line forces the pump to work harder.
Can I drive with P4068?
You can drive short distances but the high current may damage the pump.
How do I prevent DEF line crystallization?
Ensure the DEF system purges properly at shutdown.
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