P048E

What it means

P048E is the generic code for a high input fault in the circuit of the position sensor or switch on exhaust pressure control valve A. The engine control unit saw a signal voltage from the valve position feedback that stayed above the expected range, usually because of a short to voltage, an open circuit in the signal or ground wire, or a faulty sensor. Where the valve sits and how it is built depends on the engine, as it is often linked to turbocharger or exhaust back-pressure control.

Symptoms

• Engine warning light on
• Reduced power or the engine going into limp mode
• Poor or inconsistent turbo boost
• Slow warm-up or poor throttle response on some engines
• Rough running or increased smoke under load
• Other exhaust pressure or turbo related codes stored

Possible causes

• Damaged, chafed, corroded or loose wiring or connector in the valve position sensor circuit (signal short to supply voltage or open ground)likely
• Faulty position sensor or switch within the exhaust pressure control valve or actuatorlikely
• Valve seized or stuck by carbon build-up, giving an implausible position feedbackpossible
• Heat damage to the actuator electronics or harness near the exhaustpossible
• Low or unstable sensor reference voltage or poor ground supply to the sensorpossible
• Fault in the engine control unitrare
• Outdated control unit software where the manufacturer has issued a known update for this faultrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including engine load, speed and temperature at the time the code set
2. Check for related codes covering the valve actuator, turbocharger, boost pressure or reference voltage, and deal with those in a logical order
3. Visually inspect the valve, actuator, harness and connector for heat damage, chafing, corrosion, bent pins and water ingress
4. Using live data, compare the commanded and actual valve position, and check whether the position signal sits fixed at a high value
5. Check the sensor reference voltage, signal and ground at the connector against the manufacturer's specification for that model
6. Test the wiring for continuity, and for shorts to voltage or ground, with the connector unplugged and the ignition off
7. Check the valve moves freely through its full range, using an actuator test if the engine supports it, and look for carbon seizure
8. Check for relevant technical service bulletins or software updates for the specific model and engine

How to fix

• Repair or replace damaged wiring, and clean or replace corroded or damaged connectors
• Replace the valve or actuator assembly if the position sensor is faulty, following the manufacturer's procedure for that engine
• Free or clean a sticking valve where the design allows, or replace it if it is seized or worn
• Restore a good sensor reference or ground supply by repairing the circuit fault
• Update the control unit software only if a known update covers this fault, and carry out any required valve adaptation or relearn afterwards

Can I keep driving?

Nearby codes

• P048DGenericExhaust Pressure Control Valve A Position Sensor/Switch Circuit Low
• P048FGenericExhaust Pressure Control Valve A Position Sensor/Switch Circuit Intermittent/Erratic