P20D7: Exhaust Aftertreatment Fuel Supply Control Circuit/Open

What it means

This code indicates an open circuit in the exhaust aftertreatment fuel supply control circuit. The affected system supplies fuel used for exhaust aftertreatment, where fitted.

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 supply control circuit operates the fuel supply used by the aftertreatment system, where fitted, to support exhaust treatment such as DPF regeneration. P20D7 indicates an open circuit in that control path, so the module may be unable to command the supply device; the affected component and circuit layout depend on the vehicle.

Common causes

Most likely first.

1. Winding or coil open
2. Pin pushed back out of connector body
3. Cracked solder joint inside the module or sensor

Symptoms

• Check-engine light on
• DPF regeneration may be delayed or incomplete
• Reduced engine power or altered driving response in some vehicles

How to diagnose it

1. Save freeze-frame data and note any regeneration status or aftertreatment fuel-supply command data available for the vehicle.
2. Use the vehicle wiring diagram to identify the aftertreatment fuel-supply control device and inspect its connector for pushed-back pins, corrosion, or looseness.
3. Inspect the identified circuit harness for breaks, chafing, heat damage, or disconnected plugs.
4. Test the supply device’s winding or coil for an open circuit according to the manufacturer’s specification.
5. Check circuit continuity from the device to the control module and inspect module connectors if the device and harness pass.

Common fixes

• Reconnect or repair loose, corroded, or pushed-back connector terminals in the identified circuit.
• Repair a broken or heat-damaged wire in the aftertreatment fuel-supply control circuit.
• Replace the supply device if its winding or coil is open to the manufacturer’s specification.
• Repair the control-module connection or module fault if testing isolates the open circuit there.

Can I keep driving?

If the vehicle runs normally, a short trip for diagnosis is generally reasonable, but regeneration may be delayed or incomplete and soot can accumulate. Reduce driving and seek prompt attention if power drops or aftertreatment warnings appear.