Volt

DTC U183B

Control modules connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the control modules. The control modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The communication for auxiliary transmission fluid pump control module and all drive motor control modules is handled through the hybrid powertrain control module 1. The auxiliary transmission fluid pump control module and the hybrid powertrain control module 1 are all internal to the power inverter module. All circuits to the auxiliary transmission fluid pump control module and hybrid powertrain control module 1 are also internal to the power inverter module. Communication diagnostics for the serial data, including control module power and earth as well as the wake-up circuits for auxiliary transmission fluid pump control module and the hybrid powertrain control module 1, are all diagnosed only from sources external to the power inverter module connector.

A supervised periodic message that includes the transmitter module availability has not been received.

The DTC U183B is a type B DTC.

The DTC U183B is a type B DTC.

Different DTCs may set in different control modules along with this DTC depending on where the fault occurs and the vehicle operating conditions when the fault occurs.

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

1. Verify that DTC U0101 is not set.

⇒	If the DTC is set, refer to DTC U0100-U02FF .

2. Verify that DTC U0073, P06E4, B1428, B1370, B1380, B1440, B1441, B1325, or P0562 is not set.

⇒	⇒ If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

Note: Use the schematic to identify the following:

•	Control module location on the high-speed GMLAN serial data circuits

•	The control module B+, ignition, earth, accessory wake-up serial data 2 and serial data circuit terminals

1. Vehicle OFF, disconnect harness connector at the K71 transmission control module (TCM).
2. Test for less than 10 Ω between each ground circuit terminal and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. If equipped, vehicle in Service Mode, verify that a test lamp illuminates between each B+ circuit terminal and earth.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the control circuits of the K71 TCM for a short-circuit to earth. If the circuits test normal, replace the K71 TCM.

4. If equipped, vehicle in Service Mode, verify that a test lamp illuminates between each ignition circuit terminal and earth.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the control circuits of the K71 TCM for a short-circuit to earth. If the circuits test normal, replace the K71 TCM.

5. If equipped, vehicle in Service Mode, verify that a test lamp illuminates between the accessory wake-up serial data 2 circuit terminal and earth.

⇒	If the test lamp does not illuminate, test the entire circuit, including the B+ circuit to the K114B hybrid powertrain control module 2, for an open-circuit/high resistance or short-circuit to earth. If the circuits test normal, replace the K114B hybrid powertrain control module 2.

6. Vehicle OFF, disconnect the harness connector at the T6 power inverter module.
7. 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. Test for less than 2 Ω in each serial data circuit between the K71 TCM and the T6 power inverter module.

⇒	If greater than the specified range, test the serial data circuit for an open-circuit/high resistance between the K71 TCM and the T6 power inverter module.

8. If all circuits test normal, replace the K71 TCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.