P2E71 code meaning
Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit High
Powertrain system Generic code P2Exx codes Check engine light
What P2E71 means
P2E71 flags the thickness sensor circuit of pack B as reading too high. Not every swelling detector is analog: LG's module patent uses a panel that slides along a ramp until it touches a contact sensor, and a Lithium Energy and Power patent fits cells with insulated contact elements that close under pressure. Ford also describes a thin wire across a weakened cell wall that tears once the wall bulges, cutting the current through it. In such switch-type layouts an open circuit and a triggered sensor can look alike, so the controller needs a defined resting level to tell them apart. No manufacturer documents P2E71 publicly. Check connectors after pack B service first; low signal is P2E72.
P2E71 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 P2E71
- Hybrid or EV warning light
- Possibly limited power or charging
Common causes of P2E71
- Most likelySensor connector in pack B not fully seated after battery work
- PossibleBroken signal or ground wire to the sensor
- Less likelySignal line shorted to a supply voltage
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 P2E71 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 71 | The exact fault in that area. |
What to do next
- Note P2E71 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 P2E71
What does P2E71 mean?
P2E71 means "Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit High". P2E71 flags the thickness sensor circuit of pack B as reading too high. It is a generic code, so it means the same on every make.
Is it safe to drive with P2E71?
Drive gently and only to a workshop. With P2E71 the car can go into limp mode (reduced power) to protect itself.
Will P2E71 fail an emissions test?
Yes, it can. P2E71 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 P2E71 to fix?
Difficulty: workshop only. A typical repair takes 1.5 to 8 hours of work. This is a job for a workshop.
Will P2E71 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.