What it means
The phase X, Y, and Z current sensors of drive motor A do not correlate within the calibrated tolerance. Sum of phase currents should be near zero.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Drive motor A has current sensors on phases X, Y, and Z so the control system can regulate motor torque and check that the phase measurements agree. P2E27 sets when the three readings fail the controller's correlation check, including the expected near-zero sum, which can point to sensor offset drift or a ground offset.
Common causes
Most likely first.
- One sensor offset drifted
- Ground offset between sensors
Symptoms
- EV/hybrid system warning light on
- Reduced motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Save freeze-frame data and compare live X, Y, and Z phase-current readings under the conditions that set the fault.
- Check for other drive motor current-sensor or ground-related codes, since they may identify which reading or shared reference is suspect.
- With the vehicle powered down as specified by the manufacturer, inspect all three phase-current sensor connectors, wiring, and shared grounds for looseness, corrosion, or damage.
- Compare the three sensor readings and their sum at the specified operating conditions, using the manufacturer's diagnostic data and tolerances.
- If the wiring and grounds pass, test each phase sensor for offset against the manufacturer's specification to identify a drifting sensor.
Common fixes
- Clean and secure corroded or loose current-sensor connector terminals.
- Repair a damaged shared ground or sensor wiring connection.
- Replace the phase-current sensor shown by testing to have an out-of-tolerance offset.
Can I keep driving?
Drive gently only if the vehicle responds normally; reduced torque or limp mode can make merging and overtaking unsafe. If propulsion becomes intermittent or the vehicle warns of shutdown, stop safely and arrange assistance.
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.