U0168: Lost communication with the vehicle security module (immobiliser)
The vehicle network is not receiving messages from the anti-theft or immobiliser module. The main risk is that the car may not start next time.
| Code | U0168 |
|---|---|
| System | Communication network |
| Group | U01xx, Lost communication with control units |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What U0168 means
The security module recognises the key and allows the engine ECU to start; on some cars it also runs the alarm. This code means it has stopped talking to the other control units over the data network. If it happens with the engine off, the immobiliser may prevent starting.
Most common causes
- Low or flat battery
- Worn key fob battery, on cars with keyless start
- Blown fuse for the security module
- Loose or corroded connector on the module or key antenna
- Damaged network wiring
- Faulty security module, or one that has lost its programming
Symptoms
- Key or security warning light on or flashing
- Engine cranks but will not fire, or starts and dies
- Key not detected message
- Alarm or locking behaving oddly
Can you drive with U0168?
With care If the car is running you can drive, but avoid switching off far from home, as it may not restart. Get it to a garage soon.
Open the bonnetthe in-depth explanation
How to check it
Try the spare key and replace the fob battery if it is old: if the other key starts the car, the key is the problem. If the module needs replacing, it usually has to be programmed to the keys by a garage with specialist equipment or by the dealer.
How to read and clear U0168 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see U0168 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- U0164 Lost communication with the HVAC control module
- U0165 The climate control control unit (rear) is not answering on the car network
- U0166 The auxiliary heater control unit is not answering on the car network
- U0167 The vehicle immobiliser control unit is not answering on the car network
- U0169 The sunroof control unit is not answering on the car network
- U016B The air conditioning compressor control unit is not answering on the car network
- U016C The fuel pump control unit B is not answering on the car network
- U016D The exhaust gas sensor module B is not answering on the car network
- U0100 Lost communication with engine control module (ECM/PCM A)
- U0101 Lost communication with transmission control module (TCM)
- U0102 Lost communication with transfer case control module
- U0103 Lost communication with the gear shift module
What does code U0168 mean?
The security module recognises the key and allows the engine ECU to start; on some cars it also runs the alarm. This code means it has stopped talking to the other control units over the data network. If it happens with the engine off, the immobiliser may prevent starting.
Can you drive with U0168?
If the car is running you can drive, but avoid switching off far from home, as it may not restart. Get it to a garage soon.
How do you clear U0168?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, U0168 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
