Pinpoint Test DF: U0424:00, U0424:80, U0424:81 Or U0424:82

Normal Operation and Fault Conditions

REFER to: Communications Network - System Operation and Component Description .

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
IPC U0424:00	Invalid Data Received From HVAC Control Module: No Sub Type Information	Sets in continuous memory in the IPC if outside air temperature data messages received from the HVAC module through the GWM are missing for 5 seconds or longer.
IPC U0424:80	Invalid Data Received From HVAC Control Module: ISO/SAE Reserved	Sets in continuous memory in the IPC if outside air temperature data messages received from the HVAC module through the GWM are missing or invalid for 5 seconds or longer.
IPC U0424:81	Invalid Data Received From HVAC Control Module: Invalid Serial Data Received	Sets in continuous memory in the IPC if outside air temperature data messages received from the HVAC module through the GWM are missing for 5 seconds or longer.
IPC U0424:82	Invalid Data Received From HVAC Control Module: Alive/Sequence Counter Incorrect/Not Updated	Sets in continuous memory in the IPC if outside air temperature data messages received from the HVAC module through the GWM are missing for 5 seconds or longer.

Possible Sources

Communication concern
GWM
HVAC module
IPC

DF1 VERIFY THE CUSTOMER CONCERN

Ignition ON.

Verify there is an observable symptom present.

Is an observable symptom present?

Yes

GO to DF2

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

DF2 CHECK THE COMMUNICATION NETWORK
- Using a diagnostic scan tool, perform the network test.
Does the HVAC module pass the network test?

Yes GO to DF3

No REFER to: Communications Network

DF3 PERFORM THE IPC (INSTRUMENT PANEL CLUSTER) SELF-TEST
- Using a diagnostic scan tool, perform the IPC self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?

Yes REFER to DTC Chart: IPC in this information.

No GO to DF4

DF4 CHECK THE GWM (GATEWAY MODULE A) DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, check the GWM Continuous Memory Diagnostic Trouble Codes (CM DTCs).
Are any Diagnostic Trouble Codes (DTCs) recorded?

Yes REFER to: Communications Network

No GO to DF5

DF5 PERFORM THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE SELF-TEST
- Using a diagnostic scan tool, perform the HVAC module self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?

Yes REFER to the Master DTC Chart.

No GO to DF6

DF6 RECHECK THE IPC (INSTRUMENT PANEL CLUSTER) DIAGNOSTIC TROUBLE CODES (DTCS)

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

Ignition OFF.

Ignition ON.

Wait 10 seconds.

Using a diagnostic scan tool, perform the continuous memory self-test.

Check the IPC Diagnostic Trouble Codes (DTCs).

Is DTC still U0424:00, U0424:80, U0424:81 or U0424:82 present?

Yes

GO to DF7

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.

DF7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

NOTE: If new modules were installed prior to the DTC being set, the module configuration may 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 module, GWM or IPC. If recent service history is found:
- verify correct replacement module was installed
  - vehicle parts build may be used to verify correct part fitment
- verify the configuration of replacement module was correct
  - re-configure 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 DF8

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

DF8 CHECK FOR CORRECT HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE OPERATION

Ignition OFF.

Disconnect and inspect the HVAC module connector.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect the HVAC module connector. 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 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 HVAC module. REFER to: Climate Control System - Vehicles With: Dual Automatic Temperature Control (DATC)/Electronic Automatic Temperature Control (EATC) . or REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC)

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.