P0A5F: Drive Motor A Phase U Current High

P0A5F reports excessive current in phase U of drive motor A, a condition the inverter treats as overcurrent. Hyundai documents it on the 2017 Ioniq Hybrid (bulletin 17-01-057-1, campaign T2J): coolant leaking inside the traction motor set the Check Engine and hybrid lights with P0A5F, P0A62 or P0A65, often together with the isolation fault P0AA6; drivers noticed weak acceleration and a dead air conditioner. The procedure runs an insulation breakdown test with the scan tool and replaces the motor if it fails. A Hyundai patent shows such inverters measure two phases and calculate the third. P0A5E is the low side, P0A5D the general U code, P0A62 and P0A65 the same overcurrent on V and W.

Symptoms

• Check Engine and hybrid warning lights
• Reduced power when accelerating
• Air conditioning inoperative (Hyundai Ioniq Hybrid)

Most likely causes

• Internal coolant leak in the traction motor causing insulation breakdown (Hyundai Ioniq Hybrid)
• Shorted winding or phase lead of drive motor A
• Inverter power stage fault in phase U
• Current sensor falsely reporting overcurrent

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 P0A5F means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• A: Hybrid or air and fuel
• 5F: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A5F?

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 P0A5F?

The most common causes are: internal coolant leak in the traction motor causing insulation breakdown (Hyundai Ioniq Hybrid); shorted winding or phase lead of drive motor A; inverter power stage fault in phase U.

Related codes

• P0A5DDrive Motor A Phase U Current
• P0A5EDrive Motor A Phase U Current Low
• P0A62Drive Motor A Phase V Current High
• P0A65Drive Motor A Phase W Current High
• P0AA6Hybrid/EV Battery Voltage System Isolation Fault

Sources

• static.nhtsa.gov: MC 10125162 9999
• 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.