P24F8: Exhaust Aftertreatment Fuel Air Purge Valve Control Circuit

What it means

A fault is detected in the exhaust aftertreatment fuel-air purge valve control circuit. The code does not specify whether the fault is an open, short, or feedback issue.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The exhaust aftertreatment fuel-air purge valve is electrically controlled by the dosing system. P24F8 indicates a fault somewhere in its control circuit, so the module cannot reliably control the valve; the code alone does not distinguish an open wire from a short or a driver fault.

Common causes

Most likely first.

1. Open or shorted control wire
2. Failed driver stage in the dosing module

Symptoms

• Check-engine light
• Aftertreatment warning light
• Reduced engine power or performance
• Increased exhaust emissions

How to diagnose it

1. Record freeze-frame data and note any related dosing-module, supply-voltage, or purge-valve codes before clearing anything.
2. Inspect the purge-valve and dosing-module connectors and harness for corrosion, loose terminals, chafing, or heat damage.
3. Check the valve coil and circuit continuity with power disconnected, using the manufacturer's wiring diagram and specifications.
4. Check for shorts to ground or power on the control wire, isolating the valve and module as directed by the manufacturer.
5. If wiring and the valve test correctly, use the approved scan-tool test to command the valve and assess the dosing module’s driver output.

Common fixes

• Reconnect or clean corroded purge-valve circuit terminals.
• Repair an open, chafed, or shorted control wire.
• Replace the purge valve if its coil is outside the manufacturer's specification.
• Repair or replace the dosing module only after its driver output is confirmed faulty.

Can I keep driving?

Short trips may be possible if there are no severe warnings or drivability changes, but avoid heavy loads and prolonged driving because emissions control may be impaired. Follow any vehicle warning that calls for reduced speed or service.