P0C37

Code

Generic P — Powertrain

Hybrid/EV Battery Temperature Sensor F Circuit Intermittent/Erratic

Brand: Generic

Type: P — Powertrain

Views: UK: 29 EN: 34 RU: 34

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Page language: EN

Causes

Loose or corroded connector/pin at the sensor or BMS
Broken or frayed wiring harness (intermittent open/short)
Short to battery positive or ground in the sensor circuit
Failed temperature sensor (thermistor)
High-resistance connection or poor ground
Water ingress or contamination at sensor or connector

Symptoms

Hybrid/EV system warning lamp or check hybrid/EV message
BMS may limit regenerative braking, charging rate, or engine/generator output
Erratic battery temperature readout or unrealistic temperature values in data stream
Possible reduced performance or limp/limited-power mode
Intermittent fault codes that may clear and return

What to check

Read stored and pending codes and freeze-frame data with a scan tool
Monitor live battery temperature sensor F values and look for spikes, dropouts or unrealistic jumps
Visually inspect sensor connector, pins and harness for damage, corrosion, contamination, or water ingress
Perform wiggle test of harness and connector while monitoring live data to reproduce intermittent behavior
Measure supply voltage to the sensor and ground integrity at the connector
Measure sensor resistance vs temperature (compare to specification/expected thermistor curve)

Signal parameters

Typical thermistor-type sensor behaviour: resistance changes with temperature (NTC common)
Expected signal voltage (varies by design): commonly ~0.1–4.9 V on the sensor signal circuit; mid-range often near ~2.5 V at ambient temperature
Common nominal resistance reference (vehicle-specific): many designs use ~10 kΩ at 25 °C; actual values vary by manufacturer
Good sensor response: smooth, monotonic resistance or voltage change when heated/cooled (no sudden jumps or open-circuit)

Diagnostic algorithm

Safety first: follow all high-voltage (HV) safety procedures and de-energize the HV system per manufacturer instructions before accessing the battery pack or connectors. Only qualified technicians should service HV components.
Step 1 — Verify code: connect a capable scan tool, read DTC P0C37 and related codes, note freeze-frame and live data for battery temperature F.
Step 2 — Visual inspection: inspect the sensor F connector, pins and harness for corrosion, moisture, bent pins, chafing, or damage. Repair obvious damage.
Step 3 — Reproduce: with the pack and vehicle in a safe state per procedures, monitor live sensor voltage/temperature while gently wiggling the harness and connector to try to reproduce the intermittent behavior.
Step 4 — Supply/ground check: backprobe the connector (or access test points) and verify reference supply voltage and ground continuity to the BMS while observing the signal. Look for intermittent supply loss or noisy ground.
Step 5 — Sensor resistance/voltage test: remove the sensor (if serviceable) or access its terminals, measure resistance at several known temperatures (ambient, warmed with heat gun, cooled with spray) and compare to expected thermistor curve or spec. Alternatively measure signal voltage change with temperature.
Step 6 — Harness continuity: check continuity and insulation resistance between the sensor and BMS connector, and check for shorts to battery positive, ground, or chassis.
Step 7 — Repair or replace: repair wiring or connector faults; replace the sensor if its resistance/voltage response is out of spec or intermittent. Replace corroded terminals or the connector as required.
Step 8 — Clear codes and verify: clear codes, re-energize the HV system per procedures, and perform a functional test/road test while monitoring sensor F values to confirm the issue is resolved.
Step 9 — If intermittent persists: swap in a known-good sensor (if available) or consult manufacturer wiring diagrams, harness routing and BMS diagnostics. Check for ECU/BMS software updates or internal BMS input faults and involve specialist HV support if needed.