P21E5 code meaning
Cylinder 5 Injector B Circuit High
Powertrain system Generic code P21xx codes Check engine light
What P21E5 means
P21E5 means the cylinder 5 B injector circuit is pulled toward supply voltage. GM documents it for the LT5 V8 of the 2019 Corvette ZR1: the FICM looks at the low side of that injector while its driver is off and treats 0.5 Ohm or less toward power as a short. The test needs a running engine and at least 11 V at the powertrain relay, runs continuously and sets a Type A fault. A low side held at supply potential can never be switched to ground, so the injector stays closed. On this engine the port injectors were added mainly to supply extra fuel under boost, so a dead unit tends to show at high load, where cylinder 5 may run lean. The low-side counterpart is P21E4; the A injector of the same cylinder reports P0274 for the same fault type.
P21E5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P21E5
- Check engine light on
- Cylinder 5 lean or hesitant at full load
- Part-load driving often feels normal
Common causes of P21E5
- Most likelyLow-side wire of the cylinder 5 B injector shorted to a supply wire
- PossibleSupply and control wire of the injector bridged in the harness
- PossibleInjector coil shorted across its terminals
- Less likelyDamaged output stage in the injection 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 P21E5 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. |
| E5 | The exact fault in that area. |
What to do next
- Note P21E5 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 P21E5
What does P21E5 mean?
P21E5 means "Cylinder 5 Injector B Circuit High". P21E5 means the cylinder 5 B injector circuit is pulled toward supply voltage. It is a generic code, so it means the same on every make.
Is it safe to drive with P21E5?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P21E5 fail an emissions test?
Yes, it can. P21E5 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 P21E5 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P21E5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.