P0A68: Drive Motor B Phase U Current High

P0A68 means the current measured in phase U of drive motor B rises above its plausible maximum, either because a real overcurrent flows, for example through damaged insulation, a winding short or a shorted power switch, or because the phase sensor reads too high. No manufacturer documents P0A68 publicly. For the motor A counterpart P0A5F, Hyundai links phase-high codes on the 2017 Ioniq Hybrid to coolant leaking inside the traction motor, together with an insulation fault. A Toyota patent explains why the inverter must react quickly: overcurrent loads the power switches and can destroy them, so the drive is cut. CARB requires monitoring of electric drive components. P0A67 is the low side, P0A6B and P0A6E cover V and W. Motor B is shut down.

Symptoms

• Hybrid warning and MIL, often with an insulation fault code
• Sudden loss of drive from motor B

Most likely causes

• Winding short or insulation breakdown in phase U of motor B (e.g. coolant ingress)
• Shorted power switch in the phase U leg of the inverter
• Phase U current sensor reading too high (gain or offset fault)

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 P0A68 means

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

Frequently asked questions

Can I keep driving with code P0A68?

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 P0A68?

The most common causes are: winding short or insulation breakdown in phase U of motor B (e.g. coolant ingress); shorted power switch in the phase U leg of the inverter; phase U current sensor reading too high (gain or offset fault).

Related codes

• P0A66Drive Motor B Phase U Current
• P0A67Drive Motor B Phase U Current Low
• P0A6BDrive Motor B Phase V Current High
• P0A6EDrive Motor B Phase W Current High
• P0A5FDrive Motor A Phase U Current High
• P0A79Drive Motor B Inverter Performance

Sources

• patents.google.com: en
• static.nhtsa.gov: MC 10125162 9999
• 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.