Damaged or corroded wiring or connector at the cell thickness sensor; Failed cell thickness sensor; Open or short circuit in the sensor signal circuit; Faulty battery management system module; Internal battery pack damage affecting sensor readings; Loose or improperly seated sensor connector

DTC codes / P2Exx · Hybrid propulsion / P2E72

P2E72Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Low

Q: What does code P2E72 mean?

Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Low. P2E72 indicates that the battery management system has detected a low-voltage signal from the cell thickness sensor circuit for battery pack B, which monitors physical changes in the cells. The computer sets this code when the sensor's output falls below the expected range, often due to a wiring fault, sensor failure, or internal battery issue.

P2E72 indicates that the battery management system has detected a low-voltage signal from the cell thickness sensor circuit for battery pack B, which monitors physical changes in the cells. The computer sets this code when the sensor's output falls below the expected range, often due to a wiring fault, sensor failure, or internal battery issue.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illumination of the hybrid/EV system warning light or check engine light
Reduced electric-only range or performance
The vehicle may enter a limp mode or refuse to start
Inconsistent state-of-charge readings or sudden drops in battery level
Often no symptoms besides the warning light

Common causes, most likely first

Damaged or corroded wiring or connector at the cell thickness sensor
Failed cell thickness sensor
Open or short circuit in the sensor signal circuit
Faulty battery management system module
Internal battery pack damage affecting sensor readings
Loose or improperly seated sensor connector

How to diagnose and fix it

Inspect the sensor wiring and connector for damage, corrosion, or looseness
Measure resistance and voltage on the sensor circuit to check for opens or shorts
Compare sensor readings with a known-good sensor or scan tool data
Replace the cell thickness sensor if faulty
Repair or replace damaged wiring or connectors
Reprogram or replace the battery management system module if necessary
Clear codes and perform a road test to verify the repair

Before replacing the battery pack

A low cell thickness sensor signal often results from a simple wiring issue rather than a failed battery pack, so always check the harness first.
The code can be set by a weak or dying 12-volt auxiliary battery causing voltage irregularities in the hybrid system.
Some vehicles require a battery management system relearn procedure after sensor replacement, which if skipped can cause the code to return.
Corrosion at the sensor connector is a common overlooked cause, especially in areas with high humidity or road salt exposure.
The cell thickness sensor is sometimes integrated into the battery pack and not serviceable separately, requiring pack replacement if confirmed faulty.

Can I keep driving with P2E72?

It is generally safe to drive with this code if the vehicle operates normally, but avoid aggressive driving or long trips until diagnosed. If the vehicle enters limp mode or shows reduced performance, seek service immediately.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.