OBD-II fault code

P22DE: Cylinder 2 Alternative Fuel Injector Control Circuit Low

What it means

The cylinder 2 alternative-fuel injector control circuit has a voltage below the expected range. This indicates an electrical circuit fault, not necessarily an injector flow problem or short to ground.

At a glance

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

How it works

The alternative-fuel injector for cylinder 2 supplies CNG, LPG, or another secondary fuel on a bi-fuel vehicle. The control module monitors its electrical drive circuit and sets this code when circuit voltage is below the expected range; the code does not by itself confirm a blocked injector or a short to ground.

Common causes

Most likely first.

  1. Short to ground
  2. Connector pins corroded - high contact resistance
  3. Harness chafing through insulation

Symptoms

  • Check engine light on
  • Misfire or rough idle on the affected cylinder
  • Increased fuel consumption
  • Possible fuel smell or smoke from exhaust

How to diagnose it

  1. Review freeze-frame data and misfire counts, noting whether the fault occurred while the engine was using alternative fuel.
  2. Inspect the cylinder 2 injector connector and wiring for corrosion, loose pins, damaged insulation, or chafing.
  3. Test the circuit for a short to ground and check continuity using the manufacturer's procedure.
  4. Test the injector winding against the manufacturer's specification to distinguish an injector fault from a wiring fault.
  5. If the injector and harness pass, test the control-module driver and connections as directed by the manufacturer.

Common fixes

  • Repair chafed wiring or insulation that is shorting the cylinder 2 circuit.
  • Clean or repair corroded cylinder 2 injector connector pins and secure the connection.
  • Replace the cylinder 2 alternative-fuel injector if it fails the specified electrical test.
  • Repair the control-module driver circuit if testing identifies it as the cause.

Can I keep driving?

Do not use alternative fuel while cylinder 2 is misfiring; continued misfire can overheat and damage the catalytic converter. If the engine runs smoothly on its other fuel, drive gently only as needed and follow the vehicle's fuel-switching instructions.

A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together

This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.

Codes for the same component