Volt

DTC P1EC1 or P1EC2

The hybrid powertrain control module 2 activates the high-voltage energy management communication enable circuit when the vehicle is on. The high-voltage energy management communication enable circuit wakes up the battery energy control module for serial data communication.

The battery energy control module compares the high-voltage energy management communication enable hardwire signal with a hybrid powertrain control module 2 serial data message indicating that the high-voltage energy management communication enable signal is active. If the high-voltage energy management communication enable hardwire signal is low when the serial data message indicates it should be high, then DTC P1EC1 is set.

P1EC1

The ignition voltage on the high-voltage energy management communication enable circuit is less than 5 V.

DTCs P1EC1 and P1EC2 are type A DTCs.

P1EC1

The ignition voltage on the high-voltage energy management communication enable circuit is at least 5 V for 10 seconds.

DTCs P1EC1 and P1EC2 are type A DTCs.

Short-circuit to earth will also set multiple no communication codes for control modules on high-voltage energy serial data bus.

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Verify that DTC P1EB9 or U185B is not set.

Note: Use the schematic to identify the high-voltage energy management communication enable circuit terminal of the control module.

1. Vehicle OFF, disconnect the X1 harness connector at the A4 hybrid battery pack.
2. Vehicle in Service Mode, verify that a test lamp illuminates between the high -oltage energy management communication enable circuit terminal 5 X1 and earth.

⇒	If the test lamp does not illuminate, test the circuit for a short-circuit to earth or open-circuit/high resistance. If the circuit tests normal, replace the K114B hybrid powertrain control module 2.

3. Vehicle OFF, and all vehicle systems OFF, all keys at least 3 metres away from vehicle, all access doors closed. It may take up to 2 minutes for all vehicle systems to power down. Verify that a test lamp does not illuminate between the high- voltage energy management communication enable circuit terminal 5 X1 and earth.

⇒	If the test lamp illuminates, test the circuit for a short to voltage. If the circuit tests normal, replace the K114B hybrid powertrain control module 2.

4. If all circuits test normal, replace the A4 hybrid/EV battery pack.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.