Mini OBD-II Error Code P1120

Mini OBD-II Major Fuel & Air Metering - Injector

Model: OBD-II | Code: P1120

Applicable Systems
Cooper Countryman Clubman Paceman

Symptoms

The ECM has detected a fuel injector circuit fault. The engine may misfire or run on fewer cylinders. DTC P1120 is stored in the Mini engine control module.

Possible Causes

  • Fuel injector coil open or short
  • Injector driver circuit fault in ECM
  • Wiring to injector corroded
  • Injector mechanically stuck

Troubleshooting Steps

  1. Step 1: Connect an OBD-II scanner and read DTCs to confirm P1120
    DTC P1120 present with freeze frame data
  2. Step 2: Inspect wiring and connectors in the affected circuit for damage, corrosion, or loose pins
    Wiring intact, connectors clean and seated
  3. Step 3: Perform component-level testing per manufacturer service manual
    Component values within spec or component confirmed faulty
  4. Step 4: Repair or replace the faulty component, clear DTC, and verify no return
    DTC cleared and does not return after a road test

How to Reset

Clear the DTC after repair using a diagnostic scanner. The code clears automatically if the fault is not detected for 3 consecutive drive cycles.

Common Replacement Parts

  • varies: Diagnose and replace the confirmed faulty component (Confirm part number via VIN at a Mini dealership)

Frequently Asked Questions

  • Q: What does P1120 mean?

    This manufacturer-specific DTC indicates a fuel & air metering - injector system fault. Refer to the vehicle's service manual for the exact diagnostic procedure.

  • Q: Can I drive with P1120?

    Limited driving is possible, but the affected system may not operate correctly. Have the vehicle diagnosed promptly to prevent potential damage.

Related Mini Fault Codes

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Source: SAE J2012 Mini Manufacturer-Specific DTC

Category: OBD-II