P0A6B: Drive Motor B Phase V Current High

P0A6B is stored when phase V of drive motor B reports more current than the operating state allows. No manufacturer documents P0A6B publicly. Two causes must be told apart: a real overcurrent from a shorted switch, a winding fault or an insulation breakdown, and a sensor that reads high because its gain or zero offset has drifted. Patents show how inverters separate them: Toyota compares a control sensor against a monitoring sensor and the commanded current, Caterpillar checks that the three phase currents still sum to about zero. CARB requires plausibility monitoring of electric drive components. P0A6A is the low side, P0A68 and P0A6E the U and W phases, P0A62 the motor A counterpart. The inverter shuts motor B down to protect itself.

Symptoms

• Hybrid warning and MIL
• Motor B cut out, reduced acceleration

Most likely causes

• Phase V current sensor gain or offset drifted high
• Shorted power switch in the phase V leg
• Winding or insulation fault in phase V of motor B

What to check, in order

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

1. Read the codes with a hybrid-compatible scanner and write down the freeze frame data
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Make sure the battery cooling air intake is clean
4. Check the 12 V auxiliary battery, which can also trigger warnings
5. Leave any high-voltage measurements to a specialized repair shop

Good to know

• It can trigger limp mode.
• It affects emissions.

What each character of P0A6B means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• A: Hybrid or air and fuel
• 6B: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A6B?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0A6B?

The most common causes are: phase V current sensor gain or offset drifted high; shorted power switch in the phase V leg; winding or insulation fault in phase V of motor B.

Related codes

• P0A69Drive Motor B Phase V Current
• P0A6ADrive Motor B Phase V Current Low
• P0A68Drive Motor B Phase U Current High
• P0A6EDrive Motor B Phase W Current High
• P0A62Drive Motor A Phase V Current High
• P0A79Drive Motor B Inverter Performance

Sources

• patents.google.com: en
• patents.google.com: en
• law.cornell.edu: 13 CCR 1968.2

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.