P2C70: Drive Motor A Phase Z Current Low

What it means

Phase Z current of drive motor A is below the expected window. Indicates open winding, short, or sensor offset.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

The inverter regulates current through drive motor A's phase Z winding, and a current sensor reports the flow to the hybrid control module. This code sets when measured phase Z current is below the expected range, which can indicate a partly open winding or a sensor offset that reads too low.

Common causes

Most likely first.

1. Phase winding partially open
2. Current sensor offset drifted

Symptoms

• EV/hybrid system warning light on
• Reduced motor power or torque
• Possible limp mode or vehicle shutdown

How to diagnose it

1. Save freeze-frame data and compare phase Z current with phases X and Y at matching motor speed and load.
2. Check for related inverter or motor codes and note whether phase Z reads low only under load or at all times.
3. Using the manufacturer's high-voltage shutdown procedure, inspect phase Z wiring, connectors, and motor terminals for looseness, corrosion, or damage.
4. Test phase Z sensor supply, ground, signal, and circuit continuity against the manufacturer's specification.
5. If the circuit checks pass, have the phase Z winding and current sensor tested for an open winding or offset drift.

Common fixes

• Reconnect or clean a poor phase Z connector.
• Repair damaged or high-resistance phase Z wiring.
• Replace the phase Z current sensor if it fails testing.
• Repair or replace drive motor A or the inverter if an internal phase Z fault is confirmed.

Can I keep driving?

Keep loads low and drive only as needed to reach a safe location or repair facility; the vehicle may limit torque or lose hybrid propulsion. Avoid hard acceleration and steep climbs.