P22DD signals an interruption in the circuit of the cylinder 2 gas injector. On many systems that circuit is not driven by the engine computer: Ford's 2003 bi-fuel CNG trucks used a separate alternative fuel control module holding drivers for both injector sets, with heavier stages for the gas injectors because they draw more current. GM's 2014 bi-fuel Silverado likewise stores gas faults in its own CNG control module (bulletin PIP5181), so a scan tool has to read that module as well. No maker documents P22DD publicly; TransEco and Ford list only the cylinder 2 Low/High codes P22DE and P22DF, and TransEco assigns an open line to Low. Look for a burnt coil or a separated connector before blaming the module.
High severity. Can I keep driving?If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
Cylinder 2 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Malfunction indicator lamp on
- Gas mode not available or ends shortly after switching
- Misfire on cylinder 2 when running on gas
Most likely causes
- Burnt-out or open coil in the cylinder 2 gas injector
- Connector at the cylinder 2 injector loose or pulled off
- Wire break between gas control module and injector
- Failed injector driver in the separate gas control module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P22DD means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 2: Fuel injection
- DD: Specific fault in that system
Frequently asked questions
Can I keep driving with code P22DD?
If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
What causes code P22DD?
The most common causes are: burnt-out or open coil in the cylinder 2 gas injector; connector at the cylinder 2 injector loose or pulled off; wire break between gas control module and injector.
Related codes
- P22DECylinder 2 Alternative Fuel Injector Control Circuit Low
- P22DFCylinder 2 Alternative Fuel Injector Control Circuit High
- P22E0Cylinder 2 Alternative Fuel Injector Control Circuit Range/Performance
- P22D9Cylinder 1 Alternative Fuel Injector Control Circuit/Open
- P0202Cylinder 2 Injector A Circuit/Open
- P0302Cylinder 2 Misfire Detected
Sources
- static.nhtsa.gov: INRD PE08063 33504P
- static.nhtsa.gov: MC 10111929 9999
- transecoenergy.com: DTC List
- law.cornell.edu: 13 CCR 1968.2
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.