P0C97

Code

Generic P — Powertrain

Hybrid/EV Battery Temperature Sensor L Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 42 EN: 58 RU: 35

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or shorted battery temperature sensor L (NTC thermistor or harness sensor)
Open circuit (broken wire) or short to ground in sensor L wiring
Corroded or loose connector at the sensor or BMS/ECU
Water intrusion or contamination at the sensor or connector
Faulty BMS/ECU input or internal short
Incorrect repair or aftermarket connector/wiring modification

Symptoms

Hybrid/EV warning lamp or BMS warning displayed
Possible pack temperature reading out of range or implausible on scan tool
Reduced charge/discharge capability or limp-home behavior from BMS
Charging inhibited or limited to protect battery
Fault code stored and possibly related codes present

What to check

Retrieve freeze frame and live data with a capable scan tool; confirm P0C97 is active and note pack temperature readings
Visually inspect sensor L, harness and connectors for damage, corrosion or moisture
Wiggle test wiring while watching live sensor signal for intermittent changes
Backprobe connector and measure sensor signal voltage and resistance at pack side and at BMS connector
Check for continuity to the BMS and for shorts to ground or battery positive
Compare sensor resistance to expected thermistor values at known temperature (room temp)

Signal parameters

Sensor type: typically NTC thermistor (resistance varies with temperature)
Reference supply: commonly 5 V reference to sensor pull-up (verify vehicle spec)
Typical signal voltage: approx. 0.05–4.95 V depending on temp and circuit design (verify service data)
Common room-temperature resistance examples: ~2 kΩ–50 kΩ depending on design (check manufacturer spec; many are ~10 kΩ at 25°C)
Expected behavior: resistance decreases as temperature rises (NTC). Open circuit = very high/OL resistance; short to ground = near 0 V signal

Diagnostic algorithm

Use scan tool to confirm P0C97, record freeze-frame and live pack temperature values. Clear the code and see if it returns.
Perform a visual inspection of the battery pack area, sensor L, connectors and harness for damage, corrosion, water, or pinch points.
With high-voltage system deactivated/isolated per vehicle safety procedures, disconnect the sensor connector and inspect pins for corrosion or bent pins.
Measure sensor resistance at the connector. Compare to expected resistance at ambient temperature (consult service data). An open or near-zero reading indicates a fault.
Backprobe the sensor signal wire at the BMS connector (or harness splice) and measure voltage with ignition/power per manufacturer procedure. Verify correct reference voltage and signal range.
Check continuity between sensor and BMS input. Check for short to ground and short to battery positive using an ohmmeter (low-voltage side only).
If wiring and connector check good but signal remains abnormal, swap with a known-good identical sensor (if accessible) or replace sensor L and retest.
If problem persists after sensor/wiring replacement, suspect BMS/ECU input fault. Verify BMS power and grounds; if confirmed, consult manufacturer for BMS diagnostics or replacement.
After repair, clear codes and perform a test drive or cycling that previously reproduced the fault. Re-check for reoccurrence and proper pack temperature reporting.

Likely causes

Wiring damage (chafed insulation, pinched harness) between pack and BMS
Corroded/contaminated connector at the temperature sensor
Failed thermistor element inside the sensor
Short to ground due to moisture or metal contact on harness

Fault status

⚠️ Status

P0C97 — Hybrid/EV Battery Temperature Sensor L Circuit fault (low/short/open). BMS has detected an invalid temperature circuit; charging or output may be limited to protect the battery.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.5 hours (varies by vehicle and access to pack/sensors)