Powertrain, generic (extended)

P21EA Cylinder 8 Injector B Circuit Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

P21EA is the ground-short code for the B injector of cylinder 8 and the last low code in GM's 2019 FICM table for the Corvette ZR1 LT5, because the V8 ends there. Cylinder 8 is the rearmost of the right bank (bank 2). The module flags 0.5 Ohm or less between the switched-off low side and ground in 20 of 25 samples of 100 ms, with the engine running and 11 V or more at the powertrain relay, as a Type A fault. Mitsubishi's four-cylinder dual-injection engine never reaches this code, and Ford treats a B-injector short on cylinder 8 as P21D6. A grounded low side can hold the injector open, so bank 2 runs rich and fuel can wash the cylinder wall. P21EB is the high fault; the A injector low fault is P0282.

Likely causes

Cylinder 8 B injector wiring chafed through to ground

Water or corrosion in the cylinder 8 injector plug

Injector shorted to its body

FICM driver stuck on

Symptoms

Check engine light on
Rich running on bank 2
Hard hot start or misfire on cylinder 8

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, fordservicecontent.com, mitsubishitechinfo.com.