Exhaust Pressure Sensor Circuit High (Generic)
The P4038 code means the vehicle's onboard diagnostic system has detected: Exhaust Pressure Sensor Circuit High (Generic). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $80 - $350 (parts and labor)
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Common Symptoms
- Check Engine Light on
- False high exhaust pressure reading
- Premature or excessive DPF regeneration
- Poor fuel economy
- Possible turbo overboost concern
Probable Causes (Ranked by Likelihood)
- Short to voltage in sensor circuit Very High
- Sensor reading high due to internal failure High
- Pinched or kinked pressure tube Moderate
- Reference voltage fault Low
Step-by-Step Diagnostic Procedure
-
Check sensor signal voltage against specification
-
Inspect pressure tubes for kinks or restrictions
-
Disconnect sensor and check for stray voltage
-
Verify reference voltage circuit
Frequently Asked Questions
Will P4038 cause too many regenerations?
Yes, a false high reading makes the PCM think the DPF is heavily loaded.
Can P4038 cause turbo issues?
On some vehicles, exhaust pressure data is also used for turbo control.
Can I drive with P4038?
You can drive short distances but fuel economy will be poor.
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