P2E72 code meaning
Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Low
Powertrain system Generic code P2Exx codes Check engine light
What P2E72 means
P2E72 means the pack B thickness sensor reports a signal below its valid floor. On a bridge-type strain gauge, the output is a small fraction of the excitation voltage that grows with strain, so losing that excitation or shorting a bridge leg to ground pulls the reading towards zero. Capacitive designs, such as a patented pressure-sensitive QTC sensor coated with indium tin oxide, depend on a measuring module that can fail the same way. LG's piezo elements in the cell gaps only output voltage under pressure, so a short across them hides real expansion. No manufacturer documents P2E72 publicly. CARB demands separate codes for low and high faults; the high side of this circuit is P2E71, pack A's low code P2E6E.
P2E72 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1.5 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2E72
- Hybrid or EV warning light
- Power or charging may be reduced as a precaution
Common causes of P2E72
- Most likelySignal line or sensor shorted to ground inside pack B
- PossibleSensor excitation or reference supply lost
- Less likelyFault in the measuring circuit of the battery monitoring module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hybrid battery pack bHybrid battery pack b thickness sensorBms
What each part of P2E72 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 72 | The exact fault in that area. |
What to do next
- Note P2E72 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 P2E72
What does P2E72 mean?
P2E72 means "Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Low". P2E72 means the pack B thickness sensor reports a signal below its valid floor. It is a generic code, so it means the same on every make.
Is it safe to drive with P2E72?
Drive gently and only to a workshop. With P2E72 the car can go into limp mode (reduced power) to protect itself.
Will P2E72 fail an emissions test?
Yes, it can. P2E72 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 P2E72 to fix?
Difficulty: workshop only. A typical repair takes 1.5 to 8 hours of work. This is a job for a workshop.
Will P2E72 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.