P0E5A: DC/DC Converter Temperature Sensor C Circuit Low
What to do
The car will drive. Watch the twelve-volt battery over the following days — a converter that derates quietly stops charging it. If the twelve-volt battery has already been replaced once and gone flat again, say so; that pattern points here.
What this code means
The circuit for the DC/DC converter's third temperature sensor is faulty.
A third temperature sensor in a converter means the same thing a seventh means in an inverter: the hot spot moves, so the sensors are coverage rather than redundancy. The argument is at P0BCC and it transfers directly.
What is specific to a converter is what its derating costs. An inverter that derates makes the car slower, which the driver notices immediately. A converter that derates stops charging the twelve-volt battery, which the driver notices three days later, in a car park. The reasoning is at P0D32.
So a temperature sensor fault here is quiet by nature, and the symptom that eventually arrives — a flat twelve-volt battery — points at a battery. A battery replaced for this comes back flat, which is the pattern worth recognising: a twelve-volt battery that fails twice is a converter question, not a battery question.
And when the converter genuinely is overheating rather than mis-measuring, the cause is usually cooling rather than the converter — the same warning as P0D24 and P0D8F. A new converter in a car with an air lock overheats too.
At or below the lower limit.
Likely causes
Start here
- Faulty DC-DC converter · specialist
- Corroded or loose connector · specialist
- Open circuit in sensor wiring · specialist
Less common
- Faulty inverter coolant pump · specialist
- Damaged wiring harness · specialist
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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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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