P2E73

Code

Generic P — Powertrain

Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 28 RU: 24

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Page language: EN

Causes

Open, short or high resistance in sensor wiring or connector
Corroded or contaminated connector or terminal at the sensor or pack harness
Failed or damaged B‑cell thickness sensor (internal fault)
Intermittent connector contact caused by vibration or chafing
Loss of reference/supply voltage or ground to the sensor
Battery pack mechanical damage causing out‑of‑range sensor reading

Symptoms

HV system warning or EV/BMS fault indicator illuminated
Reduced drivability or limp mode (reduced performance or disabled EV drive)
Reduced charging ability or charge inhibited by BMS
Stored and/or active DTC(s) related to battery pack sensors or pack integrity
Possible audible click/relay behavior or pack isolation changes when fault present

What to check

Obtain freeze‑frame data and full DTC list from scan tool; note any related codes
Follow vehicle manufacturer high‑voltage safety procedures before any pack inspection
Visually inspect sensor connector(s), wiring harness, and pack entry points for damage, corrosion, water intrusion or pin push‑outs
Check for continuity and resistance of sensor wires between the sensor and BMS connector (compare to spec or other cell sensors)
Measure sensor supply/reference voltage and ground at the connector with ignition/HV state per OEM procedure
Monitor live sensor data (voltage, counts, or displacement) while exercising pack or performing a controlled mechanical input if safe

Signal parameters

Typical sensor type: analog displacement/position sensor (voltage output proportional to thickness). Exact type varies by vehicle
Expected supply/reference: commonly 5.0 V (verify with OEM data); sensor ground common to BMS ground
Typical signal range: ~0.5 V to ~4.5 V (midscale ~2.5 V) for proportional sensors — confirm with OEM specs
DTC may set when signal is outside expected range, shows no change, is shorted to supply/ground, or is intermittent
Some sensors may use PWM or frequency output — expected frequency and duty cycle must be checked per manufacturer data

Diagnostic algorithm

Read and record all stored codes, freeze‑frame and live data. Note vehicle state (HV on/off, SOC, temperature).
Ensure HV system is made safe per OEM procedures before physical inspection of pack or connectors.
Visually inspect B‑cell thickness sensor and wiring for damage, loose connectors, corrosion or contamination.
With power applied per OEM instructions, measure sensor supply voltage, ground integrity, and sensor output at the connector. Compare readings to spec or to another cell sensor if available.
Perform continuity and resistance checks from the sensor pins back to the BMS connector with the pack isolated. Check for shorts to ground or supply.
Monitor live sensor output while performing a controlled mechanical variation (if safe) or while gently manipulating the harness/connector to reproduce the fault.
If wiring and connectors pass, substitute a known‑good sensor (if available) or bench‑test the suspect sensor per OEM test method.
If sensor and wiring are good, suspect BMS input circuit or software. Check related communication codes and update/consult OEM technical service bulletins for software updates or calibration procedures.
After repair or replacement, clear codes and perform drive/charge cycle and any required BMS initialization or relearn procedures. Recheck for return of the code.

Likely causes

Wiring harness chafe or connector corrosion at the B‑cell sensor
Failed sensor element (common failure mode for displacement sensors)
Loose or damaged connector pins causing intermittent signal
Water ingress or contamination inside pack area affecting sensor
Faulty BMS input circuit or blown internal fuse for sensor supply

Fault status

⚠️ Status

Hybrid/EV Battery Pack B Cell Thickness Sensor Circuit Performance — sensor output out of expected range, intermittent, or inconsistent with expected cell thickness data. BMS may limit operation until condition is resolved.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5 - 4.0 hours