What it means
The current sensor for drive motor A phase Y reports a circuit low fault. Phase current measurement is unreliable.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Drive motor A's phase Y current sensor feeds phase-specific current information to the control module. P2E21 sets when the phase Y circuit signal is below the expected level, making the module's phase Y current reading unreliable.
Common causes
Most likely first.
- Current sensor failed
- Wiring fault
- Connector pins corroded - high contact resistance
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Record scan-tool freeze-frame data and determine whether the low phase Y signal occurs continuously or only during motor operation.
- Compare live phase Y sensor data with phases X and Z to verify that the low reading is specific to phase Y.
- With the vehicle safely disabled according to its service instructions, inspect the phase Y connector and harness for corrosion, loose pins, damage, or a short to ground.
- Check phase Y circuit power, ground, signal wiring, and connector contact resistance using the manufacturer's procedure.
- If the wiring passes, test the phase Y sensor against the manufacturer's specification before replacing it.
Common fixes
- Reconnect and secure the phase Y sensor connector.
- Clean or repair corroded phase Y connector pins and restore good contact.
- Repair an open, shorted, or damaged wire in the phase Y sensor circuit.
- Replace the phase Y current sensor if it still produces a low signal with the circuit verified.
Can I keep driving?
Minimise driving and avoid high torque demands because reduced power, limp mode, or shutdown may follow. If the vehicle cannot keep pace safely or gives a shutdown warning, stop safely and arrange service.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.