OBD-II code · Powertrain (generic)
P0078 Exhaust Valve Control Solenoid Circuit Bank 1
Generic electrical fault on the exhaust-valve control solenoid for bank 1. The exhaust control valve modulates exhaust backpressure or routing (EGR feed, sound, regen support); a malfunction shifts torque mapping and may trigger limp mode.
Is it safe to drive with P0078?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySolenoid coil failed
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Exhaust Valve Solenoid, Solenoid Wiring
Related codes
- P0084Exhaust Valve Control Solenoid Circuit Bank 2
- P0075Intake Valve Control Solenoid Circuit Bank 1
- P0076Intake Valve Control Solenoid Circuit Low Bank 1
- P0077Intake Valve Control Solenoid Circuit High Bank 1
- P0079Exhaust Valve Control Solenoid Circuit Low Bank 1
- P007ACharge Air Cooler Temperature Sensor Circuit Bank 1
- P007BCharge Air Cooler Temperature Sensor Circuit Range/Performance Bank 1
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.