Bolt EV Wiring Harness Connection

Some 2017-2020 Bolt EV models may have a loss of propulsion, an illuminated Malfunction Indicator Lamp (MIL) and DTCs P0A3F (Drive Motor Position Sensor Circuit) and/or P1B03 (Drive Motor Position Sensor Circuit Tracking Lost) set in the Hybrid/EV Powertrain Control Module. The vehicle may operate normally after the vehicle is restarted at a later time.

These conditions may be caused by a spread terminal on the vehicle harness connection X2 on the T12 transmission assembly. (Fig. 9) The terminals may not have been properly aligned during installation. The terminals do not need to have visible damage in order to set DTCs P0A3F and P1B03.


Fig. 9


If these conditions are found, replace the vehicle harness. Due to the sensitivity of the resolver (motor position sensor) circuits, replacing the connector with a terminated lead is not recommended.

When connecting the new harness to X2 on the transmission, use care to align the connector bodies and that the connector is fully seated. (Fig. 10)


Fig. 10


Do not attempt to install the connector at an angle. (Fig. 11)


Fig. 11


Refer to Bulletin #19-NA-220 for additional information and part numbers.


– Thanks to Lane Rezek


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