OBD-II fault code

P22DD: Cylinder 2 Alternative Fuel Injector Control Circuit/Open

What it means

The drive circuit for the cylinder 2 alternative-fuel injector is open. Bi-fuel vehicles have a second set of injectors for CNG, LPG, or hydrogen — separate from the petrol/diesel injectors.

At a glance

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

How it works

On a bi-fuel vehicle, the alternative-fuel injector supplies secondary fuel to cylinder 2, separately from its petrol or diesel injector. The control module monitors the cylinder 2 injector drive circuit and sets this code when it detects an open circuit that may stop that injector from operating.

Common causes

Most likely first.

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

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. Check freeze-frame data and cylinder-specific misfire counts, and note whether the engine was using alternative fuel when the fault set.
  2. Inspect the cylinder 2 alternative-fuel injector connector for a backed-out pin, corrosion, a poor fit, or harness damage.
  3. Test the cylinder 2 injector winding and circuit continuity using the manufacturer's procedure to locate an open.
  4. Trace the wiring from the cylinder 2 injector to the control module and check for breaks or loose connections.
  5. If the injector and wiring pass, test the module driver and its connections according to the manufacturer's diagnostic procedure.

Common fixes

  • Seat or repair a backed-out cylinder 2 injector connector pin.
  • Repair an open or damaged wire in the cylinder 2 injector circuit.
  • Replace the cylinder 2 alternative-fuel injector if its winding is open.
  • Repair the control-module connection or driver if testing confirms it is faulty.

Can I keep driving?

Avoid running on alternative fuel if cylinder 2 is misfiring; an active misfire can damage the catalytic converter and worsen fuel use. If the engine runs smoothly on its other fuel, drive gently only as needed and switch fuels according to the vehicle's 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