P24AE

Reductant Injector Circuit High Bank 1

P24AE is a generic OBD-II powertrain diagnostic trouble code: Reductant Injector Circuit High Bank 1. 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
P24AE
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P24AE means

P24AE is stored when the ECM or after-treatment control module detects a higher-than-expected voltage on the control circuit of the Bank 1 DEF/AdBlue reductant dosing injector. The reductant injector meters urea solution into the exhaust stream upstream of the SCR catalyst to enable NOx reduction.

A circuit high fault on the injector control line typically results from a short to voltage, a failed injector coil with an internal fault, or a wiring harness issue. Because precise injection timing and quantity are critical for SCR conversion efficiency, a faulty injector circuit will reduce NOx reduction capability and may trigger NOx exceedance codes alongside this fault.

The diagnostic process should begin with wiring inspection and circuit voltage checks before the injector is replaced. Many instances of this code are resolved by repairing corroded connectors or chafed wires in the harness section running from the dosing module to the injector at the exhaust pipe.

Common causes

Most-frequently reported root causes when P24AE is logged.

  • 1
    Short to battery voltage on the reductant injector control wire.
  • 2
    Failed reductant injector solenoid with internal electrical fault.
  • 3
    Damaged wiring harness near hot exhaust components causing insulation breakdown.
  • 4
    Corroded or contaminated injector electrical connector.
  • 5
    Faulty after-treatment dosing control module output driver.
  • 6
    Incorrect wiring splice or repair introducing voltage back-feed.
  • 7
    DEF crystallisation around the injector body affecting electrical connections.

Symptoms drivers notice

MIL or SCR warning lamp illuminated.
Reduced SCR NOx conversion efficiency.
Possible NOx sensor fault codes stored alongside P24AE.
SCR system may enter a reduced dosing or disabled mode.
No immediate driveability impact but emissions compliance is affected.

How to diagnose P24AE

A typical diagnostic flow when this code is present.

  1. 1
    Read all DTCs; document any companion SCR, NOx sensor, or reductant delivery codes.
  2. 2
    Inspect the reductant injector wiring harness along its full length from the dosing module to the injector.
  3. 3
    With the injector connector unplugged and ignition on, check for unexpected voltage on the control pin.
  4. 4
    Measure injector coil resistance and compare to specification.
  5. 5
    Check the dosing module connector and ground circuit for integrity.
  6. 6
    If wiring and injector check out, evaluate the dosing module for an internal driver fault.
  7. 7
    Clear codes after repair and verify with a drive cycle including SCR operating conditions.

Vehicles where we've handled P24AE

Platforms in our catalogue with confirmed P24AE coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

Will P24AE cause DEF injection to stop completely?

The system may reduce or halt injection to protect the injector and circuit; this will reduce SCR effectiveness and can lead to NOx-over-limit fault codes.

Can DEF contamination cause P24AE?

DEF crystallisation around the injector body can bridge electrical contacts or corrode the connector, potentially causing circuit faults.

Is there a Bank 2 version of this code?

Yes, some larger diesel engines with dual SCR banks have a corresponding Bank 2 code; P24AE is specific to Bank 1.

How do I know if the injector itself is bad versus the wiring?

Unplug the injector connector and measure coil resistance; if it is out of specification, the injector is suspect. If resistance is normal, focus on the wiring and control module.

Disabling P24AE in software

RaceTune can permanently disable P24AE — 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 P24AE 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 EDC17C50 verified 1 software version
  • Bosch EDC17CP09 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.

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