Pinpoint Test CE: Abs Module Communication Concern With HVAC

Normal Operation and Fault Conditions

With the ignition ON, the HVAC control module sends messages to the ABS module over the HS-CAN3 through the GWM. If the ABS module does not receive these messages within the allotted time frame or if the messages contain invalid data, the module sets a DTC. This can be due to a HVAC control module failure, a circuit failure on the network or an excessive load on the network. For information on the messages sent to the ABS module by the HVAC control module, REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
ABS U0164:00	Lost Communication With HVAC Control Module 'A': No Sub Type Information	This DTC sets when the ABS module does not receive any messages from the HVAC control module within the allowed time.

Possible Causes

Network communication concern
GWM
HVAC control module

CE1 CHECK THE COMMUNICATION NETWORK

Ignition ON.

Using a diagnostic scan tool, carry out the Network Test.

Does the HVAC pass the Network Test?

Yes	DIAGNOSE the HVAC Diagnostic Trouble Codes (DTCs). REFER to: Climate Control System . If thre are no HVAC Diagnostic Trouble Codes (DTCs), GO to CE3

GO to CE2

CE2 CHECK THE GWM (GATEWAY MODULE A) COMMUNICATION

Review the results of the modules communicating on the network from the previous step.

Does the GWM pass the network test?

Yes	DIAGNOSE the HVAC module does not communicate with the diagnostic scan tool. REFER to: Controller Area Network (CAN) Module Communications Network .

No	DIAGNOSE the GWM module does not communicate with the diagnostic scan tool. REFER to: Controller Area Network (CAN) Module Communications Network .

CE3 RECHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE DTCS

Using a diagnostic scan tool, clear the ABS module Diagnostic Trouble Codes (DTCs).

Put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.

Ignition ON.

Using a diagnostic scan tool, carry out the ABS module self-test.

Are any of the DTCs in the Fault Trigger Conditions Table retrieved again?

Yes

GO to CE4

No	The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

CE4 CHECK FOR VOLTAGE-RELATED DIAGNOSTIC TROUBLE CODES (DTCS) IN THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE
- Review the recorded Diagnostic Trouble Codes (DTCs) from the ABS module.
Is DTC U3003:16 or U3003:17 present in the ABS module?

Yes For ABS module DTC U3003:16, GO to Pinpoint Test A For ABS module DTC U3003:17, GO to Pinpoint Test F

No GO to CE5

CE5 RETRIEVE ALL DTCS FROM THE GWM (GATEWAY MODULE A)
- Using a diagnostic scan tool, carry out the GWM self-test.
- Record all DTCs from the GWM module self-test.
Are any DTC present?

Yes DIAGNOSE the GWM Diagnostic Trouble Codes (DTCs). REFER to: Controller Area Network (CAN) Module Communications Network .

No GO to CE6

CE6 RETRIEVE ALL DTCS FROM THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE
- Using a diagnostic scan tool, carry out the HVAC self-test.
- Record all DTCs from the HVAC module self-test.
Are any DTC present?

Yes DIAGNOSE the HVAC Diagnostic Trouble Codes (DTCs). REFER to: Climate Control System .

No GO to CE7

CE7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

NOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly set during the PMI or the PMI may not have been carried out.

Check the vehicle service history for recent service actions related to the HVAC or ABS module. If recent service history is found:
- VERIFY the correct replacement module was installed.
  - HVBOM may be used to verify correct part fitment.
- VERIFY the configuration of replacement module was correct.
  - re-configure the module using as-built data if prior configuration is suspect.
- VERIFY the module was not obtained from a like vehicle and installed into customer vehicle.
  - return the swapped module to source vehicle and obtain new replacement module.

Operate the system and determine if the observable symptom is still present.

Is the observable symptom still present?

Yes

GO to CE8

No	The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

CE8 CHECK FOR COMMUNICATION DIAGNOSTIC TROUBLE CODES (DTCS) IN OTHER MODULES
- Ignition ON.
- Clear the ABSDTC.
- Using a diagnostic scan tool retreve all Diagnostic Trouble Codes (DTCs).
Is DTC U0164:xx or U0424:xx set in one or more modules in addition to the ABS module?

Yes GO to CE9

No GO to CE10

CE9 VERIFY HVAC (HEATING, VENTILATION AND AIR CONDITIONING)OPERATION

Ignition OFF.

Disconnect HVAC C228A.

Disconnect GWM C2431A.

Using a good light source, inspect all disconnected electrical connectors for the following:
- Corrosion - install new connector or terminal and clean the module pins
- Damaged or bent pins - install new terminals or pins
- Pushed-out pins - install new pins as necessary
- Spread terminals - install new terminals as necessary

Connect GWM C2431A. Make sure it seats and latches correctly.

Connect HVAC C228A. Make sure it seats and latches correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new HVAC. REFER to: Heating, Ventilation and Air Conditioning (HVAC) Control Module .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues. Refer to CONNECTOR REPAIR PROCEDURES for schematic and connector information.

CE10 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

Put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.

Disconnect ABS module C135.

Disconnect GWM C2431A.

Using a good light source, inspect all disconnected electrical connectors for the following:
- Corrosion - install new connector or terminal and clean the module pins
- Damaged or bent pins - install new terminals or pins
- Pushed-out pins - install new pins as necessary
- Spread terminals - install new terminals as necessary

Connect GWM C2431A. Make sure it seats and latches correctly.

Connect ABS module C135. Make sure it seats and latches correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

The HCU and ABS module are a single assembly known as the EBB unit. CHECK OASIS for any service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new EBB module. REFER to: Electric Brake Booster (EBB) .

No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues. Refer to CONNECTOR REPAIR PROCEDURES for schematic and connector information.