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U0100



DTC U0100-U0299 (HP2)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC U0100 00
- Lost Communication With ECM/PCM

DTC U0101 00
- Lost Communication With TCM

DTC U0102 00
- Lost Communication With Transfer Case Control Module

DTC U0104 00
- Lost Communication With Cruise Control Module

DTC U0109 00
- Lost Communication With Fuel Pump Control Module

DTC U010F 00
- Lost Communication With Air Conditioning Control Module

DTC U0121 00
- Lost Communication With Anti-Lock Brake System (ABS) Control Module

DTC U0122 00
- Lost Communication With Vehicle Dynamics Control Module

DTC U0129 00
- Lost Communication With Brake System Control Module

DTC U0132 00
- Lost Communication With Ride Level Control Module

DTC U0134 00
- Lost Communication With Power Steering Control Module - Rear

DTC U0137 00
- Lost Communication With Trailer Brake Control Module

DTC U0140 00
- Lost Communication With Body Control Module

DTC U0141 00
- Lost Communication With Body Control Module A

DTC U0146 00
- Lost Communication With Gateway "A"

DTC U0151 00
- Lost Communication With Restraints Control Module

DTC U0151 71
- Lost Communication With Restraints Control Module Invalid Serial Data Received

DTC U0151 7F
- Lost Communication With Restraints Control Module Erratic

DTC U0155 00
- Lost Communication With Instrument Panel Cluster (IPC) Control Module

DTC U0156 00
- Lost Communication With Information Center A (DIC)

DTC U0158 00
- Lost Communication With Head Up Display

DTC U0159 00
- Lost Communication With Parking Assist Control Module

DTC U0160 00
- Lost Communication With Audible Alert Control Module

DTC U0164 00
- Lost Communication With HVAC Control Module

DTC U0165 00
- Lost Communication With HVAC Control Module - Rear

DTC U0168 00
- Lost Communication With Vehicle Security Control Module

DTC U0170 00
- Lost Communication With Restraints System Sensor A (PPS)

DTC U0172 00
- Lost Communication With Rollover Sensor

DTC U0184 00
- Lost Communication With Radio

DTC U0186 00
- Lost Communication With Audio Amplifier

DTC U0198 00
- Lost Communication With Telematic Control Module

DTC U0199 00
- Lost Communication With Door Control Module A (DDM)

DTC U0200 00
- Lost Communication With Door Control Module B (PDM)

DTC U0208 00
- Lost Communication With Seat Control Module A (DSM/MSM)

DTC U0209 00
- Lost Communication With Seat Control Module B (HVSM)

DTC U0210 00
- Lost Communication With Seat Control Module C (RHVSM)

DTC U0214 00
- Lost Communication With Remote Function Actuation

DTC U0241 00
- Lost Communication With Headlamp Control Module A

DTC U0249 00
- Lost Communication With Entertainment Control Module - Rear B

DTC U0293 00
- Lost Communication With Hybrid Powertrain Control Module

Diagnostic Fault Information






Circuit/System Description

Modules connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The 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 serial data gateway module (SDGM) activates the hybrid serial data wake up circuit by applying voltage when the ignition key is in ACC, ON or START. The only modules activated by the hybrid serial data wakeup circuit are the hybrid powertrain control module (HPCM) which is part of the traction power inverter module (PIM), and the battery pack control module (BPCM).

Conditions for Running the DTC

* The system voltage is between 9-16 volts.
* The vehicle power mode master indicates the power mode RUN.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

The modules is never signaled, therefore the specific subsystems will not function.

Conditions for Clearing the DTC

* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Diagnostic Aids

* Use the DTC Descriptor list above to determine the module which is not communicating.
* Use the Hybrid High Voltage Module Chart to determine if a specific module is a high voltage module.
* Use Data Link References to determine which serial data communication system a specific module uses.
* If there are multiple non-communicating modules choose the one closest to the data link connector (DLC).
* Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.

Circuit/System Verification

With a scan tool, ensure the following DTCs are not present:

* B137A
* B137B
* U1814
* U2099

If a DTC listed above is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle before proceeding with this diagnostic. Diagnostic Trouble Code Descriptions

Circuit/System Testing

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks:

* Identify how to disable high voltage

* Identify how to test for the presence of high voltage

* Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

* Failure to follow the procedures exactly as written may result in serious injury or death.

1. Using the Hybrid High Voltage Module Chart, verify that the non-communicating module is not a high voltage module.

^ If the module is a high voltage module, perform the High Voltage Disabling procedure before proceeding with this diagnostic.

2. Reconnect the 12-volt battery.
3. Ignition OFF, disconnect the necessary harness connectors of the non-communicating module.
4. Test for less than 1 ohm between all ground circuits and ground.

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

5. Ignition ON, verify that a test lamp illuminates between all battery positive voltage circuits and ground.

^ If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.

Important: Not all modules have a serial data communication enable circuit OR accessory wakeup serial data circuit. Refer to the module schematics to identify which modules have these circuits. If the module that is not communicating does not have one of these circuits, proceed to step 7.

6. Ignition ON, verify that a test lamp illuminates between the serial data wake up or communication enable circuit, if equipped, and ground.

^ If the test lamp does not illuminate, test the circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the module that supplies voltage to the wake up or enable circuit.

7. Using the Hybrid High Voltage Module Chart, verify that the module reporting the DTC is not a high voltage module.

^ If the module is a high voltage module, perform the High Voltage Disabling procedure before proceeding with this diagnostic.

8. Reconnect the 12-volt battery.
9. Ignition OFF, disconnect the harness connector containing the serial data circuits of the module that reported the DTC.
10. Test for less than 1 ohm on the serial data (+) circuit between the module reporting the DTC and the non-communicating module.

^ If greater than the specified range, test the serial data circuit for open/high resistance.

11. Test for less than 1 ohm on the serial data (-) circuit between the module reporting the DTC and the non-communicating module.

^ If greater than the specified range, test the serial data circuit for open/high resistance.

12. If all circuits test normal, replace the non-communicating module.






Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* GMLAN Wiring Repairs
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