Electrical system and control unitsGeneric OBD-II codeUrgency: Monitor
Code U0164: loss of communication with the climate control module
U0164 means: loss of communication with the climate control module (HVAC: heating, ventilation and air conditioning).[1][2][3] The climate control module (HVAC) and other modules in the car cannot communicate with each other. The communication circuit is the control area network, the CAN bus, according to CódigosDTC.[1]
What code U0164 means
The climate control module (HVAC) and other modules in the car cannot communicate with each other. The communication circuit is the control area network, the CAN bus, according to CódigosDTC.[1]
According to TaT (in a Ford-based description), the code is stored when a receiving module does not receive valid CAN messages from the climate control module within a calibrated time with the ignition on. The “20” variant of that entry indicates a timeout, that is, communication has been lost rather than the data being invalid. AutoDTCs lists it as a loss of CAN bus communication with the fully automatic temperature control (FATC).[2][4]
It is a generic network code (DTCSearch classifies it as controlled by ISO/SAE), so it means the same on any brand.[3]
Original definition (SAE J2012): Lost Communication With HVAC Control Module[1][2][3]
Causes of U0164
From most to least likely, according to the sources.
Symptoms
- Engine fault warning light on.[1]Engine warning light: faults that cause it
- The climate control module does not work: the heating or air conditioning controls do not respond.[1]
How to diagnose U0164
In order: from the most likely and cheapest to check to the most expensive.
- 1Consult the model's technical bulletins and look for other stored codes, especially on the CAN network; read all the modules to see whether any others are missing.[1][2]
- 2Using the car's information, locate the fuses that power the climate control module, check them and check their connections; repair what is needed.[1]
- 3Disconnect the battery negative cable and the climate control module connector; inspect the connectors and wiring for burns or heavy corrosion and correct it.[1]
- 4With the module connector disconnected, check that it receives power and earth according to the wiring diagram, and correct whatever is missing.[1]
- 5Check the integrity of the CAN bus and the power and earth of each module, as a general starting point for U codes (TaT).[2]
Can I keep driving with U0164?
Monitor
The sources do not give a specific severity. AutoDTCs rates it as moderate under its general communication (U) guide, and the symptom CódigosDTC cites is that the climate control does not respond, not that driving is affected. It is worth monitoring and checking at the workshop: if other communication codes also appear or other modules stop responding, it is no longer an isolated climate fault and must be treated as a network problem.[1][2][4]
Parts related to code U0164
The parts that most often cause this code. The code points to the circuit, not always the part: diagnose before you buy.
Air con compressor
Affiliate links: if you buy from these shops, MotorFiable may receive a commission at no cost to you. Check compatibility against the registration plate or VIN before ordering. Affiliate links
Documented faults related to U0164
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Air conditioning: the most serious faults by engine and car
- Critical severityFrequency: CommonCitroën Berlingo IIIAir conditioning compressor stator wiring faultTwo successive recalls, in 2023 and 2024, cover Berlingo IIIs built between 2021 and 2024 in which the air conditioning compressor stator wiring can fail and even switch the engine off while driving; a reliability survey also documents a genuine compressor failure at 30,200 km.Appears at around 30,200 km
- Critical severityFrequency: CommonPeugeot RifterAir conditioning compressor stator wiring faultTwo successive recalls, in 2023 and 2024, cover Rifters built between 2021 and 2024 in which the air conditioning compressor stator wiring can develop a current fault and even switch the engine off while driving; owner reports also document genuine compressor failures.
- Critical severityFrequency: OccasionalKia Sorento IIIOverheating of the climate control's auxiliary electric heater (PTC) connector on diesel SorentosYes: Kia recalled diesel Sorentos built between May 2014 and February 2020 (campaign 221026) because the connector of the auxiliary electric heater (PTC) can become damaged and overheat, with a risk of fire. The connector is inspected and, if damaged, the heater is replaced along with its wiring.
- Critical severityFrequency: OccasionalPorsche Panamera IShort circuit in the air conditioning fan control unitYes: the 2019 recall AKA7 covers Panamera cars built between July 2009 and September 2016 because the air conditioning fan control unit can short circuit, with a risk of fire. It is inspected and, if necessary, replaced; in the UK it affected 4,506 cars.
Control units and comfort electronics (BSI, SAM...): the most serious faults by engine and car
- High severityFrequency: CommonPeugeot 408Electronic faults with the doors, boot and screen (suspected BSI control unit)In 2025 Peugeot recalled around 60,000 2023-2024 Peugeot 308 and 408 cars (code MUV) over a software fault in the door control unit that can cause unintended opening or closing and disable the anti-trap protection on the windows; 408 owners also describe a power boot lid that will not open or close and a screen that goes black.
- High severityFrequency: CommonRenault Laguna IIMultiplex electrical system and hands-free card faultsThe Laguna II had a reputation problem because of faults in its multiplexed electrical network: the hands-free card, the card reader and the ABS, ESP and handbrake warning lights came on erratically, especially in the early years of production (2001-2003).
- Critical severityFrequency: OccasionalMazda MX-5 IVDC/DC converter control unit fault with risk of short circuit and fireA 2018 Safety Gate alert covers MX-5 ND models built between August 2014 and April 2017: the DC converter control unit could fail, cause a short circuit and damage the converter, with a risk of fire. It is a precautionary recall; check the chassis number at the official service centre.
- Medium severityFrequency: Very frequentFiat StiloElectrical and electronic faults in the multiplex systemThe Stilo has had a reputation for widespread electrical faults since its launch: poor contacts in the multiplex wiring, an instrument cluster that switches off and sensors that disconnect, sometimes while the car is running.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Main relay of the power relay assembly (overheating and fire risk)Yes, on the first units: Hyundai and Kia recalled 2016–2018 Ioniq and Niro hybrids and plug-in hybrids because the main relay that connects the high-voltage battery could come loose, overheat and, in the worst case, cause a fire.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fireYes, this is the most documented hybrid system fault: the hydraulic actuator that engages the combustion engine with the hybrid assembly has had two recalls (2018 for a leak on the Niro and 2025 for moisture in its electronic board on the Niro, Ceed and XCeed PHEV), with a risk of short circuit and fire.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
What does HVAC mean?
It is the English abbreviation for heating, ventilation and air conditioning. The code refers to the control module of that system.[1][3]
Is it the climate control module that is failing?
Not necessarily. CódigosDTC places CAN bus faults (open circuit, short circuit) before the module itself, and TaT recommends checking the network, the power supply and the earth of each module and reading all the others before deciding.[1][2]
Why does the engine warning light come on with a climate control fault?
CódigosDTC lists the engine fault warning light among the symptoms of the code, but does not explain why.[1]
What should I check first?
The technical bulletins and the other stored codes, and then the module's power fuses, its connectors, and the power and earth at the connector, in that order.[1]
Will I pass the MOT with code U0164?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[5]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- U0164 - Comunicación perdida con el módulo de control de HVACCódigosDTC · Technical documentation · consulted 31 October 2026 · in Spanish
- U0164 (20) - Lost Communication With HVAC Control ModuleThe Automotive Technician (TaT) · Technical documentation · consulted 31 October 2026
- U0164 - Lost Communication With HVAC Control ModuleDTCSearch · Technical documentation · consulted 31 October 2026
- U0164 - CAN Communication bus with fully automatic temperature control (FATC) (timeout)AutoDTCs · Technical documentation · consulted 31 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish