P220A

Reductant Pump Control Circuit High

P220A is a generic OBD-II powertrain diagnostic trouble code: Reductant Pump Control Circuit High. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P220A
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
Need P220A disabled?
RaceTune permanently disables any OBD-II trouble code on supported ECUs — for motorsport, off-road, and export use.
→

What P220A means

P220A is stored when the SCR or engine control module detects a higher-than-expected voltage on the reductant pump control circuit. It is the high-side counterpart to P208A (control circuit low) and is triggered when the monitored voltage exceeds the calibrated upper limit during a commanded pump event or during a rationality check.

A high-voltage condition on this circuit is commonly caused by an open circuit in the pump wiring that allows the control line to float up to supply voltage, a broken pump motor winding, a disconnected or backed-out connector pin, or a short to a battery-voltage source on the control wire. When the pump control circuit is open, the module cannot drive current through the load and detects the unloaded high voltage on its output sense path.

Diagnosis should begin with a physical inspection of the wiring harness and connector for open circuits and damage, followed by pump motor resistance measurement and supply/ground verification. Module driver diagnosis should be a last step after all external causes are excluded.

Common causes

Most-frequently reported root causes when P220A is logged.

  • 1
    Open circuit in the reductant pump control wiring or harness.
  • 2
    Disconnected or backed-out terminal at the pump connector.
  • 3
    Failed pump motor with an open winding.
  • 4
    Short to battery voltage on the pump control wire.
  • 5
    Broken pump ground connection.
  • 6
    Corroded connector causing high-resistance or open path.
  • 7
    Internal SCR module output driver failure.

Symptoms drivers notice

MIL illuminated with P220A stored.
Reductant pump does not operate, resulting in no pressure in the DEF supply line.
No reductant dosing, potentially causing NOx efficiency faults.
SCR or AdBlue warning lamp active on the instrument cluster.
Derate condition possible if the pump remains non-functional over an extended period.

How to diagnose P220A

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all stored DTCs and freeze-frame data with a scan tool.
  2. 2
    Inspect the reductant pump harness and connector for open circuits, damaged pins, or corrosion.
  3. 3
    Disconnect the pump connector and measure motor winding resistance to check for an open circuit.
  4. 4
    Verify the pump supply voltage and ground connections are within specification.
  5. 5
    Reconnect the connector, command the pump on via scan tool, and measure control circuit voltage live.
  6. 6
    If voltage is high during commanded pump operation, trace the control wire for an open or short to supply between the pump and module.
  7. 7
    If wiring and pump resistance are correct but the fault persists, suspect an internal module driver fault and consult manufacturer procedures.

Vehicles where we've handled P220A

Platforms in our catalogue with confirmed P220A coverage.

MB GLE350 30D
MB GLC220 21D
2017

Related powertrain codes

Frequently asked questions

Is P220A dangerous to ignore?

Yes. Without a functioning reductant pump there is no DEF dosing, which will degrade NOx conversion and eventually trigger a derate that limits vehicle performance.

Can unplugging and re-plugging the pump connector clear P220A?

If a backed-out or corroded pin was causing an open circuit, reseating the connector may resolve the fault. However, a test drive is needed to confirm the fault does not return.

How do I tell P220A (high) from P208A (low)?

P220A indicates the circuit voltage is above the expected range, typically caused by an open circuit. P208A indicates the circuit voltage is below the expected range, typically caused by a short to ground.

Will the pump run at all with P220A active?

Generally not. The open or high-voltage circuit condition prevents the module from properly energizing the pump motor, so the pump typically remains inoperative while the fault is set.

Disabling P220A in software

RaceTune can permanently disable P220A — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECUs with a P220A disable in our catalogue

Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.

  • Bosch EDC17C60 verified 2 software versions
  • Bosch EDC17CP57 verified 2 software versions
  • Bosch EDC17C66 verified 1 software version
  • Bosch MD1CP004 verified 1 software version

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

Got P220A in your scan?

Upload your ECU file — we'll identify the exact software version and confirm whether a disable is available for your car.

Upload your file