P0C6E: Hybrid/EV Battery Temperature Sensor A/B Correlation
What to do
Do not let this be dismissed as a sensor fault before the alternative is ruled out. Two neighbouring sensors disagreeing means either one is wrong or one has genuinely found a hot area of the battery — and the second is worth knowing about early. The discriminator is behaviour: a real hot spot grows under load and fades when the car cools; a faulty sensor is indifferent to both.
What this code means
Battery temperature sensors A/B are reporting temperatures that do not agree.
The check is simple and the physics behind it is what makes it trustworthy: heat moves. Two sensors sitting near each other in the same pack cannot be at very different temperatures, because the material between them conducts. So a disagreement larger than the pack's geometry allows means something is wrong — and the chain of these codes walks the whole pack, each sensor checked against its neighbour.
What it cannot say is which of the two is at fault, the same honesty as every correlation check in this corpus. But the second possibility is the one not to dismiss. Either a sensor is lying, or one of them is telling the truth about a hot spot — and a single area of a battery running hotter than the material around it is precisely what an early internal cell fault looks like.
That is why a correlation code deserves more attention than a plain sensor circuit code, not less. A circuit fault is an instrument problem. This might be the pack's first warning about itself, and the way to tell is whether the hot reading tracks load and recovers on cooling — a real hot spot does, and a faulty sensor does not care what the car is doing.
Likely causes
Start here
- Faulty battery temperature sensor · specialist
Less common
- Weak or failed cell group in the battery pack · specialist
- Corroded or loose connector · easy
- Faulty battery pack sensor module · specialist
- Blocked hybrid battery cooling fan intake · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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