P0078: Exhaust Valve Control Solenoid Circuit — Bank 1
What to do
Usually driveable. Expect a lumpier idle until it is repaired.
What this code means
An electrical fault in the bank 1 exhaust valve control solenoid circuit. Exhaust-side valve control has a strong influence on how much burnt gas is retained in the cylinder, so faults here often show first as an unstable idle rather than as a loss of peak power.
Likely causes
Start here
- Failed valve control solenoid · moderate
- Open circuit in solenoid wiring · moderate
- Corroded or loose connector · easy
Rare
- Control module driver failure · specialist
Symptoms
Components involved
Information, not instruction
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Community experience
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