Powertrain, generic (extended)

P21E9 Cylinder 7 Injector B Circuit High

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

P21E9 indicates that the low side of the cylinder 7 B injector carries supply voltage. On GM's 2019 Corvette ZR1 LT5, the FICM declares this when it sees 0.5 Ohm or less to power with the driver off, provided the engine runs and the powertrain relay delivers 11 V or more; Type A, one trip. The rear left cylinder then gets only its direct injector. As the extra port fuel on this engine is meant for boosted operation, the effect may be limited to full throttle, where bank 1 can turn lean. CARB demands that output components be checked for circuit faults, yet leaves it to the maker whether shorts to power get their own code; GM separates them, while Ford folds every B-injector short into the open code (here P21D5). Low fault: P21E8; A injector high: P0280.

Likely causes

Cylinder 7 B injector control wire shorted to battery voltage

Injector coil with too low resistance

Injection control module driver defective

Symptoms

Check engine light on
Bank 1 lean at full throttle
Less power at full throttle

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–900

Time1–4 h

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

Parts involved

fuel injectorinjector wiringengine control module

References: gsi.ext.gm.com, law.cornell.edu, fordservicecontent.com.