U0627 code meaning
Lost Communication With A/C Refrigerant Temperature Sensor A
What U0627 means
Refrigerant temperature matters most where a controller adjusts superheat itself, as with electronic expansion valves and heat pumps; it also guards against overheated discharge gas. U0627 is set once the digital temperature value from sensor A is no longer received. Many suppliers build temperature and pressure into one housing; Sensata, for example, offered such R744 sensors with LIN, PWM or analog output. If U0626 appears at the same moment, the shared plug, LIN line or supply of that combined part is the first suspect; if only U0627 is present, the temperature channel or a separate sensor is more likely. No manufacturer documents U0627 publicly. Depending on the strategy, cooling or heat-pump output drops or stops. Analog equivalents are P0EBC to P0EBF.
U0627 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0627
- Reduced cooling or heat-pump output
- Heat-pump mode unavailable, auxiliary heater takes over
- A/C fault message
Common causes of U0627
- Most likelyConnector, LIN line or supply of a combined pressure/temperature sensor faulty
- PossibleTemperature channel or sensor electronics failed
- Less likelyClimate or thermal controller no longer polls the sensor (software or LIN master fault)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ac refrigerant temp sensor aVehicle bus wiring
What each part of U0627 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 27 | The exact fault in that area. |
What to do next
- Note U0627 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 U0627
What does U0627 mean?
U0627 means "Lost Communication With A/C Refrigerant Temperature Sensor A". Refrigerant temperature matters most where a controller adjusts superheat itself, as with electronic expansion valves and heat pumps; it also guards against overheated discharge gas. It is a generic code, so it means the same on every make.
Is it safe to drive with U0627?
U0627 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0627 fail an emissions test?
U0627 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 U0627 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will U0627 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.