P0E72: Control Pilot Signal Low Frequency
What to do
Try a different charge point — this usually means the charger, not the car. If the car charges normally elsewhere, report the faulty unit to whoever operates it. If it happens everywhere, the car's pilot circuit needs checking.
What this code means
The Control Pilot signal's frequency is below specification.
The Control Pilot is a 1 kHz square wave, and the frequency is not decoration — it is how the car knows the signal is a real pilot rather than noise.
The full handshake is at P0CF3. In short: the charge point puts a square wave on one pin, and the pulse width states how much current the car may draw; the car replies by switching resistors to pull the voltage down in defined steps. A charge point will not energise the cable until it sees a valid reply.
The frequency is the carrier that whole conversation rides on, and the standard pins it at 1 kHz precisely so that width can be measured against it. Measuring a pulse width means comparing it against the period — so a frequency that has drifted makes every current limit the car calculates wrong, not merely suspect.
Which is why this code usually means the supply rather than the car. A vehicle measuring an out-of-specification frequency is reporting on the equipment it is plugged into, and the single most useful test is another charge point.
Low frequency is the commoner direction and points hardest at the charge point. A pilot generator that has drifted low stretches every pulse, so the car reads a wider pulse than intended and would draw more current than the supply can give — which is precisely the failure the frequency check exists to catch, and why the car refuses rather than trusting it.
Try another charge point before anything else. A car that charges normally elsewhere has diagnosed the first one.
Likely causes
Start here
- Fault in the external charging equipment · easy
- Corroded or loose connector · specialist
Less common
- Damaged charging inlet or pins · moderate
- Faulty on-board charger · 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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