What it means
The exhaust pressure control valve A circuit signal is lower than expected. Possible causes include a wiring or connector fault, an actuator fault, or a control-module issue.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Exhaust pressure control valve A is operated through a control circuit, and the module monitors the circuit signal while commanding the valve. This code sets when the signal is lower than expected, which can result from a control wire shorted to ground, a failed actuator, or a connector fault.
Common causes
Most likely first.
- Short to ground in valve control wiring
- Exhaust pressure control valve actuator failure
- Corroded or loose connector
- Fault in the control module
Symptoms
- Check-engine light on
- Reduced exhaust-brake performance, if equipped
- Possible reduced engine power
- DPF regeneration problems or warning, where equipped
How to diagnose it
- Record freeze-frame data and check related valve A, exhaust-brake, or DPF codes to see when the low circuit signal occurred.
- Inspect valve A's connector for looseness, corrosion, moisture, or damaged terminals.
- Trace the valve A control wiring for chafing or a short to ground, especially near hot or moving components.
- Check whether valve A or its linkage is physically stuck, without forcing the valve beyond the vehicle's service procedure.
- Test the actuator circuit for a short to ground and verify its supply, ground, and control connections against the wiring diagram and manufacturer's specification.
- If the circuit is sound, test the actuator or solenoid; check the control module only after wiring and actuator faults have been ruled out.
Common fixes
- Reconnect and secure the valve A connector.
- Clean or repair corroded connector terminals.
- Repair control wiring shorted to ground or damaged by heat or rubbing.
- Replace the failed valve A actuator or solenoid.
- Repair or replace the control module only if testing confirms its output is faulty.
Can I keep driving?
If equipped with an exhaust brake, assume it may not work correctly and leave extra stopping distance; do not rely on it on steep descents. Avoid demanding operation if power is reduced or a DPF warning appears, and arrange repair promptly.
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.