P21E2: Cylinder 4 Injector B Circuit Low

What does P21E2 mean?

P21E2 is the low fault of the B injector on cylinder 4, the last cylinder of an inline four. It is the final direct injector low code in Mitsubishi's 2022 Eclipse Cross list, which uses B for the high-pressure injectors and sets it for an open or a short to ground lasting 2 s. If the engine has lost injectors on more than one cylinder, the control unit stops direct injection completely and limits torque, so a P21E2 stored together with other P21DB-series codes points to a shared cause such as the intermediate connector or the driver supply. The cylinder 4 port injector reports P0270 and P0271. GM's 2019 LT5 V8 uses P21E2 for the right-bank cylinder 4 supplemental injector, rating a low side under 0.5 Ohm to ground as Type A. P21E3 is the high fault.

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

Symptoms

• Check engine light on
• Misfire on cylinder 4 (P0304)
• Noticeably less power with several codes (port injection only)

Common causes

• High Cylinder 4 injector wire open or shorted to ground
• Medium Intermediate connector fault affecting several cylinders
• Medium Cylinder 4 injector coil defective

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