P0E72: Control Pilot Signal Low Frequency

P0E72 refers to the pulse train that an AC charging station places onto the pilot wire. Under SAE J1772, matched by IEC 61851-1, this is a rectangular ±12 V signal at 1 kHz, and its duty cycle tells the car how much current it may draw. The vehicle measures the period of this signal; if it is clearly slower than 1 kHz, the reading is distrusted and P0E72 is stored, because a wrong frequency also makes the current limit unreliable. No manufacturer documents P0E72 publicly. A US Department of Energy test report on pilot-line communication (PNNL) treats the 1000 Hz frequency and pulse width as values that added equipment must not disturb. Causes are a faulty station or adapter, interference on the line, or the car's measuring circuit. P0E73 is the high case; voltage faults are P0CF4 to P0CF6.

Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.

Symptoms

AC charging does not start or stops at one station
Charging works normally at other stations

Most likely causes

Charging station or portable charger generating an off-spec pilot
Faulty charging adapter or extension in the cable path
Pilot measuring circuit in the vehicle charger misreading

What to check, in order

Start with the simplest. You can tick off each step.

Check the battery, connectors, and wiring
With the connector unplugged, check whether the signal wire is making contact with ground.
Read the live data with a scanner
Follow the manufacturer's service manual

Good to know

Repair difficulty: easy

What each character of P0E72 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
E: Subsystem depends on the code range
72: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0E72?

If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.

What causes code P0E72?

The most common causes are: charging station or portable charger generating an off-spec pilot; faulty charging adapter or extension in the cable path; pilot measuring circuit in the vehicle charger misreading.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.