U0164 code meaning
Lost Communication With HVAC Control Module
Network system Generic code U01xx codes Check engine light
What U0164 means
U0164 is stored by any module that stops hearing the HVAC control module, the unit that runs blower, flaps and temperature selection. GM documents two monitors in its 2025 tables (25OBDG03B): the body control module watches several HVAC frames and flags a gap longer than 12.5 s at 11-18 V, and the central gateway reacts after 6.5 s once a frame is overdue by 2.5 times its period; both are Type B, so the MIL can come on after two trips. Ford SSM 47040 (Escape 2017-2018) finds U0164 in the BCM and starts with a battery reset; GM PIT5586G and Stellantis case S2308000122 (Wagoneer) trace it to gateway or inline bus connectors. U0165 is the rear unit, U010F the A/C module. Climate controls go dead.
U0164 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0164
- Climate control panel dark or not responding
- Blower, temperature or defrost stuck at last setting
- Check engine light on some GM models after two trips
- Code stored in several modules at once
Common causes of U0164
- Most likelyLoose or spread terminals at gateway or inline bus connectors
- PossibleHVAC module without power or ground
- PossibleIncomplete module configuration or hung module, cleared by battery reset (Ford)
- Less likelyHVAC control module faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hvac control moduleCAN bus wiring
What each part of U0164 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 64 | The exact fault in that area. |
What to do next
- Note U0164 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0164
What does U0164 mean?
U0164 means "Lost Communication With HVAC Control Module". U0164 is stored by any module that stops hearing the HVAC control module, the unit that runs blower, flaps and temperature selection. It is a generic code, so it means the same on every make.
Is it safe to drive with U0164?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0164 fail an emissions test?
U0164 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0164 to fix?
Difficulty: medium. A typical repair takes 0.3 to 3 hours of work. This is a job for a workshop.
Will U0164 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.