Inverter power module or phase current sensor fault; Damaged, chafed or loose high-voltage phase cable or connector to the motor (phase U); Drive motor winding short or insulation breakdown; Motor position (resolver) sensor or its wiring giving wrong rotor angle, causing excessive current; Inverter or motor overheating from a cooling system fault (low coolant, failed pump, blocked flow); Low-voltage supply or control unit fault causing incorrect current control.

P0A68

Drive Motor B Phase U Current High.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
A: AreaHybrid propulsion
68: FaultThe specific fault in that area

What it means

P0A68 means the hybrid or electric drive control unit detected current in phase U of drive motor 'B' above the permitted limit. It is set when the measured phase current, normally from the inverter's current sensing, exceeds a threshold, which can point to a short, an inverter fault or a control problem. Which motor is 'B' depends on the vehicle, so check the manufacturer's information for your model.

Symptoms

Hybrid or EV system warning light on, often with a master warning
Reduced power or limp-home mode
Vehicle will not enter ready mode or shuts down the drive system
Judder, hesitation or jerky response under acceleration
Engine running more than normal on a hybrid, or reduced regenerative braking

Possible causes

Inverter power module or phase current sensor faultlikely
Damaged, chafed or loose high-voltage phase cable or connector to the motor (phase U)likely
Drive motor winding short or insulation breakdownpossible
Motor position (resolver) sensor or its wiring giving wrong rotor angle, causing excessive currentpossible
Inverter or motor overheating from a cooling system fault (low coolant, failed pump, blocked flow)possible
Low-voltage supply or control unit fault causing incorrect current controlrare

How to diagnose

Only a technician trained in high-voltage systems should work beyond reading data. Read all stored and pending codes and the freeze frame data (speed, load, temperatures, battery voltage and phase currents) to see the conditions when it set.
Check for related codes covering the position sensor, inverter, cooling system or high-voltage insulation, and deal with those first.
Check the inverter and motor coolant level, condition and circulation, and look for pump or flow faults.
Check the 12 V battery condition and charging, since low voltage can upset the control units.
Visually inspect the high-voltage phase cables, shielding and connectors between inverter and motor for damage, corrosion, heat marks or looseness.
After isolating the high-voltage system using the manufacturer's procedure and proving it dead, test phase resistance balance and insulation resistance of the motor and cables.
Check the motor position sensor wiring, connector and signal against specification.
If the wiring and motor test fine, compare live phase current data with expected values and check the inverter against the manufacturer's test procedure.

How to fix

Repair or replace damaged high-voltage phase cables or connectors, using the correct procedure and parts
Replace the inverter or its faulty module or current sensor if testing confirms it
Replace or repair the drive motor if windings or insulation fail testing
Repair or replace the position sensor or its wiring
Restore proper cooling by topping up or replacing coolant, bleeding the system or replacing a faulty pump
Clear the code and road test once repairs are done, confirming it does not return

Can I keep driving?

High severity

Avoid driving. A high phase current fault can mean a short or failing inverter, which risks sudden loss of drive and further damage to expensive high-voltage components. If the vehicle runs in limp mode, only move it a short distance to a safe place or workshop, preferably by recovery.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.