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DTC codes / P0Cxx · Hybrid propulsion / P0C71

P0C71Hybrid/EV Battery Temperature Sensor D/E Correlation

P0C71 indicates that the hybrid or electric vehicle battery pack's temperature sensor D and sensor E are reporting values that do not correlate as expected, meaning the battery energy control module sees a disagreement between two sensors that should track closely. The computer sets this code when the temperature readings from these two sensors differ by more than a calibrated threshold for a sustained period, often indicating a faulty sensor, wiring issue, or battery pack problem.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light or hybrid system warning light, often with no other noticeable symptoms.
  • Reduced hybrid system performance or a forced limp mode in some vehicles.
  • Inconsistent or erratic battery temperature readings on a scan tool.
  • Possible reduced electric-only range or charging issues if the battery management system limits power.
  • In rare cases, a burning smell or unusual noises from the battery pack area if overheating is involved.

Common causes, most likely first

  1. Faulty temperature sensor D or E within the battery pack.
  2. Damaged or corroded wiring or connectors between the sensors and the battery energy control module.
  3. Poor electrical connection at the sensor harness or module.
  4. Battery energy control module software needing recalibration or update.
  5. Internal battery pack issue such as a failing cell affecting local temperature.
  6. Failed battery energy control module (less common).

How to diagnose and fix it

  1. Use a scan tool to retrieve all stored codes and freeze-frame data, then clear codes and test-drive to see if P0C71 returns.
  2. Visually inspect the battery pack wiring harness and connectors for damage, corrosion, or loose pins.
  3. Measure resistance of both temperature sensors and compare to specifications; replace if out of range.
  4. Check for continuity and short circuits in the wiring between the sensors and the control module.
  5. Verify sensor signal voltages at the control module connector with a multimeter while monitoring live data.
  6. If wiring and sensors are good, check for technical service bulletins or software updates for the battery energy control module.
  7. As a last step, consult a dealer or specialist for battery pack internal diagnosis or module replacement.

Sensor correlation faults are rarely just the sensor

  • A correlation code between two temperature sensors often results from a wiring issue rather than a failed sensor, so always inspect the harness before replacing parts.
  • The battery energy control module may set this code due to a software glitch; check for updates before condemning hardware.
  • Temperature sensor D and E are typically located within the same battery module, so a local hot spot from a failing cell can cause a correlation error.
  • Some vehicles require a battery pack disassembly to access the sensors, making this a job for a qualified hybrid technician.
  • Clearing the code without addressing the root cause may lead to repeat failures and potential battery damage if temperatures are not monitored correctly.

Can I keep driving with P0C71?

It is generally safe to drive with this code if the vehicle is operating normally, but avoid aggressive driving or heavy loads that could stress the battery. If the hybrid system warning light is on or performance is reduced, have the vehicle inspected promptly to prevent potential battery damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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