P21E3 code meaning
Cylinder 4 Injector B Circuit High
Powertrain system Generic code P21xx codes Check engine light
What P21E3 means
P21E3 marks a high circuit state on the cylinder 4 B injector, normally a short to a supply line. On Mitsubishi's 2022 Eclipse Cross, where B is the direct high-pressure injector, the fault must persist 2 s; it closes the manual's list of direct injector circuit codes for the four cylinders. Because the direct injector driver uses boosted voltage, Mitsubishi tells technicians not to probe the terminals with a voltmeter and to work with resistance and continuity checks instead. GM's 2019 LT5 V8 assigns the same code to the supplemental injector of cylinder 4, stored as Type A when the low side sits within 0.5 Ohm of power with the driver off. The low counterpart is P21E2, the port injector high code on Mitsubishi P0271; from P21E4 on, the series continues with cylinder 5.
P21E3 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P21E3
- Check engine light on
- Misfire on cylinder 4 (P0304)
- Engine runs with reduced torque if further cylinders are affected
Common causes of P21E3
- Most likelyCylinder 4 injector line shorted to a supply wire
- PossibleInjector of cylinder 4 shorted internally
- Less likelyDriver stage in the ECM or injection module damaged
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel injectorInjector wiringEngine control module
What each part of P21E3 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 1 | Area: fuel and air metering. |
| E3 | The exact fault in that area. |
What to do next
- Note P21E3 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P21E3
What does P21E3 mean?
P21E3 means "Cylinder 4 Injector B Circuit High". P21E3 marks a high circuit state on the cylinder 4 B injector, normally a short to a supply line. It is a generic code, so it means the same on every make.
Is it safe to drive with P21E3?
Drive gently and only to a workshop. With P21E3 the car can go into limp mode (reduced power) to protect itself.
Will P21E3 fail an emissions test?
Yes, it can. P21E3 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P21E3 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P21E3 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.