Network
generic / SAE
U0165
Lost Communication with Auxiliary HVAC Control Module
A control module that expects to talk to the engine ECU has stopped receiving messages. Most commonly seen by the TCM, instrument cluster, or BCM after the ECU has been disconnected, fitted with a faulty replacement, or the CAN wiring has been damaged. Engine usually will not run while this fault is active in other modules.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number1 / 65
Possible causes
- Auxiliary HVAC module unpowered high
- CAN wiring to auxiliary HVAC broken medium
- Gateway module routing CAN messages incorrectly low
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–1000 €
- Estimated time: 1–4 h
- Component: hvac control module
- Component: can bus wiring
Sources
References
sae:J2012