Exhaust Pressure Control Valve B Low

Where it lives

For P04A1, the part to look at first is the valve named here.

Check these first

• A valve B reading lower than commanded
• A failed exhaust pressure sensor
• An underboost condition feeding the valve
• A leaking intake or charge pipe

What to do next

1. Compare commanded and actual valve B position on a scan tool
2. Check the exhaust pressure sensor signal
3. Smoke test the intake and charge pipes for a leak
4. Replace the exhaust pressure sensor if its signal is off
5. Clear the code and retest

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