What does it mean?
An intermittent fault means the module saw the second exhaust pressure control valve circuit go out of range briefly and then return to normal, rather than failing steadily. The monitoring routine records short voltage spikes, momentary dropouts or a feedback signal that jumps in a way real valve movement cannot explain.
Codes of this type almost always come from a mechanical connection problem in the circuit rather than a component that has actually failed: a terminal that loses contact under vibration, insulation rubbing that only touches ground on rough roads, or a connector that loses its seal when hot. The valve often works perfectly during a workshop test, which is exactly what makes this code frustrating. Diagnosis has to be aimed at reproducing the dropout instead of measuring static values.
Symptoms
- MIL (check engine lamp) that comes on and later goes off by itself
- Complaints that appear only in wet weather, over rough roads or after long high load driving
- Warm up performance and heater output that are normal on most days but poor occasionally
- Regeneration that is interrupted without an obvious reason
- Other intermittent codes on nearby circuits stored in the same time frame
Likely causes
- Loose, corroded or spread terminals in the valve connector or an inline connector in the harness
- Wiring chafing on a bracket or heat shield that only contacts ground when the engine rocks or the road is rough
- Connector seal damage letting moisture in, so the fault appears after washing or in wet weather
- Cracked solder joint or a partly broken conductor inside the harness under the insulation
- Heat related dropout in the valve winding that only appears at full operating temperature
- Poor module or engine ground connection producing erratic reference voltages across several circuits
How to fix it
- Compare freeze frame data from each occurrence and look for a shared condition such as road speed, temperature or weather
- Set the scan tool to graph the valve circuit while performing a systematic wiggle test on the connector, the loom and each harness support
- Open the valve connector and inspect terminal tension, seal condition and any sign of green corrosion or moisture
- Check every ground point shared by the module and the exhaust management circuits, cleaning and retorquing as needed
- Run a voltage drop test across the control and ground legs while the valve is actuated, since a bad joint shows up under load and not at rest
- Heat the suspected harness area gently or spray it with water to reproduce the dropout, then repair the section rather than replacing parts
- Clear the code and drive under the same conditions recorded in freeze frame to confirm the repair