U0168: Lost communication with the vehicle security module (immobiliser)

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.

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 this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

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 the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

• U0146 Lost communication with gateway A
• U0151 Lost communication with the restraints control module
• U0155 Lost communication with the instrument cluster
• U0164 Lost communication with the HVAC control module
• U0184 Lost communication with the radio
• U0198 Lost communication with the telematics control module
• 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

U0168 is a generic code, so it means the same on any make, for example on Abarth, Cupra, Jeep, Nissan, Seat, Škoda. See what Final OBD does on your car in makes and models.