P22E8 Cylinder 4 Alternative Fuel Injector Control Circuit Range/Performance

P22E8 applies when the cylinder 4 gas injector circuit is complete but the measured response lies outside the plausible range, for instance an opening current that rises too slowly or a hold phase that never settles. No vehicle maker documents P22E8 openly; the published lists from TransEco and Ford end at Low/High. Gas quality is a frequent background factor: GM fits a coalescing filter with a 6 micron element in its bi-fuel pickups because contaminants and liquids in the gas can damage the injectors, and the filter has to be drained and replaced at intervals. A neglected filter can therefore show up as this code. Cleaning rarely helps; the injector or the complete rail is usually replaced, then a drive on gas confirms the repair.

Likely causes

Symptoms

• Malfunction indicator lamp on
• Rough idle on gas, smooth on gasoline
• Gas mode ends after a while

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: static.nhtsa.gov, law.cornell.edu, http:.