P21E1 code meaning
Cylinder 3 Injector B Circuit High
Powertrain system Generic code P21xx codes Check engine light
What P21E1 means
P21E1 is the high fault on the cylinder 3 B injector circuit. In Mitsubishi's 2022 Eclipse Cross that is the direct high-pressure injector, and the module reacts to a short circuit lasting 2 s, checked with 10 to 16.5 V battery voltage. To confirm a repair, the manual points to its OBD drive cycle pattern 1. GM's 2019 LT5 V8 monitors the low side of the supplemental cylinder 3 injector in its separate FICM module and flags under 0.5 Ohm toward power as Type A with the MIL in the first trip. A short to power keeps the low side from ever reaching ground, so the injector cannot open, and switching against the short can strain the driver stage. P21E0 covers the low fault and P0268 the port injector high fault on Mitsubishi; a cylinder 3 misfire often follows.
P21E1 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 P21E1
- Check engine light on
- Cylinder 3 not firing properly
- Torque reduction if several injectors fail (Mitsubishi)
Common causes of P21E1
- Most likelyCylinder 3 injector line shorted to supply voltage
- PossibleShorted injector coil
- Less likelyDamaged driver in the control module
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 P21E1 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. |
| E1 | The exact fault in that area. |
What to do next
- Note P21E1 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 P21E1
What does P21E1 mean?
P21E1 means "Cylinder 3 Injector B Circuit High". P21E1 is the high fault on the cylinder 3 B injector circuit. It is a generic code, so it means the same on every make.
Is it safe to drive with P21E1?
Drive gently and only to a workshop. With P21E1 the car can go into limp mode (reduced power) to protect itself.
Will P21E1 fail an emissions test?
Yes, it can. P21E1 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 P21E1 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P21E1 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.