P0A63: Drive Motor A Phase W Current

P0A63 concerns the current in phase W of drive motor A. In the Toyota field reports filed with NHTSA it always appears beside P0A60: on a 2006 Highlander Hybrid with sub code 502, after P0A60 sub code 501, together with P0A78 and P0AEF, master warning on and no drive; the inverter assembly was replaced. These Toyota reports name only V and W, for the motor and for the generator (P0A72, P0A75), which fits a design where two phase currents are measured and U follows from the rule that all three add up to zero, as a Hyundai patent describes. Audi stores P0A6300 in module J841 of the 2021-23 Q5 e quattro when the welded high-voltage phase lead fails. P0A64/P0A65 are low and high, P0A5D and P0A60 phases U and V.

Symptoms

• Master warning or drive system fault message, MIL
• Vehicle will not move or start

Most likely causes

• Internal fault in the inverter assembly (Toyota Highlander Hybrid)
• High-voltage phase W cable or weld joint faulty (Audi Q5 e quattro)
• Phase W current sensor failed

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. Make sure the battery cooling air intake is clean
3. Check the 12 V auxiliary battery, which can also trigger warnings
4. 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 P0A63 means

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

Frequently asked questions

Can I keep driving with code P0A63?

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 P0A63?

The most common causes are: internal fault in the inverter assembly (Toyota Highlander Hybrid); high-voltage phase W cable or weld joint faulty (Audi Q5 e quattro); phase W current sensor failed.

Related codes

• P0A64Drive Motor A Phase W Current Low
• P0A65Drive Motor A Phase W Current High
• P0A5DDrive Motor A Phase U Current
• P0A60Drive Motor A Phase V Current
• P0A75Generator Phase W Current
• P0A78Drive Motor A Inverter Performance

Sources

• static.nhtsa.gov: INRD PE11005 45763P
• static.nhtsa.gov: MC 10234548 0001
• patents.google.com: en

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.