What it means
The drive circuit of the exhaust pressure regulator vent solenoid is open. The solenoid releases pressure from the exhaust backpressure regulator, which is part of the exhaust brake system on diesel trucks.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The exhaust pressure regulator vent solenoid releases pressure from the exhaust backpressure regulator, commonly used as part of a diesel truck's exhaust brake system. The control module monitors the solenoid drive circuit and sets this code when it detects an open circuit, so the solenoid may not operate when commanded.
Common causes
Most likely first.
- Solenoid winding open
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Exhaust brake may not operate as expected
- Reduced engine braking on descents
- Possible change in exhaust backpressure or engine performance
How to diagnose it
- Read freeze-frame data and check related codes, then confirm whether the exhaust brake or backpressure regulator fault appeared during a solenoid command.
- With the system safely cool, inspect the vent solenoid connector and harness for disconnection, damage, corrosion, or a terminal pushed back into the connector.
- Check the solenoid winding for an open circuit using the manufacturer's test procedure and compare the result with its specification.
- With the solenoid disconnected as directed by the service information, test continuity through the drive wiring and check for an open between the solenoid and control module.
- If the wiring and solenoid pass, inspect the relevant module or sensor connections and follow the manufacturer's circuit diagnosis before considering an internal module fault.
Common fixes
- Reconnect the vent solenoid connector or repair a loose or backed-out terminal.
- Repair an open or damaged wire in the solenoid drive circuit.
- Replace the exhaust pressure regulator vent solenoid if its winding is open.
- Repair an internal module connection only after the external circuit tests pass.
Can I keep driving?
The exhaust brake may provide less engine braking, so allow extra stopping distance and use the service brakes carefully on descents. Avoid relying on the exhaust brake until its operation is restored.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.