P21DE code meaning
Cylinder 2 Injector B Circuit Low
Powertrain system Generic code P21xx codes Check engine light
What P21DE means
P21DE is the low fault of the cylinder 2 B injector circuit. In Mitsubishi's 2022 Eclipse Cross manual, B means the direct injector; the code covers both a break and a grounded wire on the two DI lines of cylinder 2, held for 2 s at 10 to 16.5 V, while the port injector of the same cylinder reports P0264. Diagnosis starts with the coil resistance at the intermediate connector, which should be 1.74 to 2.04 Ohm at 20 °C. On GM's 2019 LT5 V8 cylinder 2 is the front cylinder of the right bank; there a low side shorted to ground on the supplemental injector, below 0.5 Ohm, sets a Type A fault from its separate module. GM runs this check while the driver is switched off; a grounded low side can energise the injector without a command. P21DF is the high fault, P21D0 the open.
P21DE 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 P21DE
- Check engine light on
- Misfire on cylinder 2 (P0302)
- Possible fuel smell or rich running if an injector stays open
Common causes of P21DE
- Most likelyInjector line of cylinder 2 touching ground
- PossibleInjector coil resistance outside specification
- PossibleFault at the intermediate connector of the injector harness
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 P21DE 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. |
| DE | The exact fault in that area. |
What to do next
- Note P21DE 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 P21DE
What does P21DE mean?
P21DE means "Cylinder 2 Injector B Circuit Low". P21DE is the low fault of the cylinder 2 B injector circuit. It is a generic code, so it means the same on every make.
Is it safe to drive with P21DE?
Drive gently and only to a workshop. With P21DE the car can go into limp mode (reduced power) to protect itself.
Will P21DE fail an emissions test?
Yes, it can. P21DE 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 P21DE to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P21DE clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.