Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test E: U0164:87
- Refer to MODULE COMMUNICATIONS NETWORK
for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Module Controlled Functions - System Operation and Component Description .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition BCMC U0164:87 Lost Communication With HVAC Control Module: Missing Message A continuous memory DTC that sets in the BCMC if data messages received from the HVAC module through the GWM are missing. Possible Sources
- Communication network concern
- HVAC module
- BCMC (BJB)
- E1 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Using a diagnostic scan tool, perform a network test.
Does the HVAC module pass the network test?
Yes GO to E2 No REFER to: Module Controlled Functions - System Operation and Component Description . - E2 CHECK THE BCMC (BODY CONTROL MODULE C) CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CMDTCS)
- Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).
- Wait 10 seconds.
- Using a diagnostic scan tool, check the BCMC Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Is BCMCDTC U0164:87 retrieved again?
Yes GO to E3 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. - E3 RETRIEVE THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, perform the HVAC module self-test.
Are any HVAC module Diagnostic Trouble Codes (DTCs) recorded?
Yes REFER to: Climate Control System - Vehicles With: Dual Automatic Temperature Control (DATC) . REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) . No GO to E4 - E4 RECHECK THE BCMC (BODY CONTROL MODULE C) CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CMDTCS)
- Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).
- Wait 10 seconds.
- Using a diagnostic scan tool, check the BCMC Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Is DTC U0164:87 still present?
Yes GO to E5 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. - E5 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0164:87 SET IN OTHER MODULES
- Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Using a diagnostic scan tool, retrieve all Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Is DTC U0164:87 set in other modules?
Yes GO to E6 No GO to E7 - E6 CHECK FOR CORRECT HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE OPERATION
- 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: 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. - E7 CHECK FOR CORRECT BCMC (BODY CONTROL MODULE C) OPERATION
- Disconnect and inspect all BCMC connectors.
- 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
- Connect the BCMC connectors. Make sure they seat and latch 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 BCMC. REFER to: Body Control Module C (BCMC) . 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.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.