P21DF code meaning
Cylinder 2 Injector B Circuit High
Powertrain system Generic code P21xx codes Check engine light
What P21DF means
P21DF is set when the cylinder 2 B injector circuit shows a short toward supply. Mitsubishi's 2022 Eclipse Cross applies it to the direct high-pressure injector and stores it after a 2 s short with the ignition on and the driver supply above 10 V; troubleshooting first inspects the negative DI wire of cylinder 2 up to the engine module and names the injector, the harness and the ECM as possible causes. The fail-safe is graded: with one cylinder affected, both injectors of that cylinder stop; with several, the engine falls back to port injection and torque is limited. GM's 2019 LT5 V8 judges the same title on its supplemental injector by less than 0.5 Ohm toward power on the low side, Type A. The port injector high code of this Mitsubishi cylinder would be P0265; P21DE is the low fault.
P21DF 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 P21DF
- Check engine light on
- Cylinder 2 switched off or misfiring
- Less pulling power with multiple faults
Common causes of P21DF
- Most likelyNegative injector line of cylinder 2 shorted to supply
- PossibleInjector coil shorted
- Less likelyECM or injection module driver defective
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 P21DF 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. |
| DF | The exact fault in that area. |
What to do next
- Note P21DF 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 P21DF
What does P21DF mean?
P21DF means "Cylinder 2 Injector B Circuit High". P21DF is set when the cylinder 2 B injector circuit shows a short toward supply. It is a generic code, so it means the same on every make.
Is it safe to drive with P21DF?
Drive gently and only to a workshop. With P21DF the car can go into limp mode (reduced power) to protect itself.
Will P21DF fail an emissions test?
Yes, it can. P21DF 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 P21DF to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P21DF clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.