Is CHG_F125 the same as CHG-F125?

Yes. CHG_F125, CHG F125, and CHG-F125 are alternate spellings of the same Tesla alert code. Also written as: CHG-F125, CHG_F125, CHG F125, CHG_f125_leakageTestFailure, chg_f125_leakagetestfailure.

What symptoms can CHG-F125 cause?

Charger alert: This fault indicates that the voltage decay after the supercharger external isolation test has happened too quickly. Dur Vehicle shows charging error immediately after plugging in Charge port light stays red or does not respond

What should I check for CHG-F125?

1. Try a different outlet or charging cable 2. Check if your circuit breaker has tripped 3. Reboot the vehicle and attempt to charge again 4. Schedule a Tesla Service appointment — the on-board charger may need replacement

Is it safe to drive with CHG-F125?

🔴 Do NOT drive. Stop safely and call for roadside assistance immediately.

TESLA Fault

CHG-F125

CHG_f125_leakageTestFailure

Also written as CHG_F125 / CHG F125 / CHG_f125_leakageTestFailure / chg_f125_leakagetestfailure

System

CHG

Charger

Type

Fault

Why does the exact Tesla alert ID matter?

Record the exact alert ID, including underscores, suffixes, and companion alerts. Tesla alerts that look similar can point to different modules, timestamps, and service procedures.

What does CHG-F125 mean?

Tesla fault code in the Charger (CHG) module. This fault indicates that the voltage decay after the supercharger external isolation test has happened too quickly. During supercharger startup, the supercharger will open the output contactors after performing the external isolation test at 300V. The vehicle then monitors the time it takes for the 300V to decay. If the decay time is sufficient, the start-up sequence proceeds. The purpose of this test is to check the common mode isolation (DC+ to DC-) of the high voltage chain from the supercharger cabinet to the vehicle's fast charge contactors.

Original Description

This fault indicates that the voltage decay after the supercharger external isolation test has happened too quickly. During supercharger startup, the supercharger will open the output contactors after performing the external isolation test at 300V. The vehicle then monitors the time it takes for the 300V to decay. If the decay time is sufficient, the start-up sequence proceeds. The purpose of this test is to check the common mode isolation (DC+ to DC-) of the high voltage chain from the supercharger cabinet to the vehicle's fast charge contactors.

Affected Tesla Models

Model SModel XModel 3Model YCybertruck

What You May Notice

Charger alert: This fault indicates that the voltage decay after the supercharger external isolation test has happened too quickly. Dur
Vehicle shows charging error immediately after plugging in
Charge port light stays red or does not respond

How to Diagnose and Resolve

1 Try a different outlet or charging cable
2 Check if your circuit breaker has tripped
3 Reboot the vehicle and attempt to charge again
4 Schedule a Tesla Service appointment — the on-board charger may need replacement

Severity Notes

CHG-F125 is classified as a Fault, indicating a critical issue in the Charger system. Do not continue driving and contact Tesla Service immediately.

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