P21E7: Cylinder 6 Injector B Circuit High

What does P21E7 mean?

P21E7 is stored when the B injector of cylinder 6 shows a short toward power. GM's 2019 Corvette ZR1 with the LT5 V8 is the documented user; there the FICM checks the low side only in the driver-off state, flags 0.5 Ohm or less to power, and needs at least 11 V at the powertrain relay with the engine running. The result is a Type A fault after one trip. With the low side tied to supply, every switching attempt would push current straight into the driver, so the injector on the right-bank cylinder 6 delivers nothing. A useful check is to unplug the injector: if the voltage on the control wire stays, the harness is at fault; if it disappears, the injector coil is suspect. P21E6 is the matching low fault and P0277 the A injector high code.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Lean condition on bank 2 under load
• Cylinder 6 misfire at high load

Common causes

• High Cylinder 6 B injector control wire in contact with a live wire
• Medium Shorted turns in the injector coil
• Low Output stage of the injection control module damaged by the short

Likelihood is a general estimate across vehicles; your make and model may differ.