Engine computer and electrics

B1681 PATS: transceiver signal not received

By: Diagno editorial team · Updated: 2026-10-15

B1681 means: PATS: transceiver signal not received. The immobiliser checks that the key is the right one. Don't drive until the car has been checked. The engine could be damaged. The repair usually costs about €60–600 in Estonia. The most common cause: key chip or battery.

Is it safe to drive?Don't driveDon't drive until the car has been checked. The engine could be damaged.

Typical repair cost€60–600parts and labour in Estonia

What it means

The immobiliser checks that the key is the right one. The computer didn't get proper confirmation from the key or immobiliser and may block the engine from starting.

This is a make-specific code (Ford). The exact meaning can vary by model and year.

What you may notice

The engine won't start or stalls straight away
Immobiliser light flashing

What could be wrong

1Key chip or battery
2Key reader coil around the ignition
3Communication between immobiliser and engine computer
4Low battery voltage

Repair difficulty: Hard

What you can check yourself

Try the spare key. If the car starts with it, the fault is in the first key. Best left to a workshop. It needs a diagnostic tool and experience.

How we fix it

We read the immobiliser data with the diagnostic tool
We check the key and reader coil
We re-learn the key or repair the system

Standard SAE description: PATS Transceiver Signal Is Not Received

This code usually comes with: Check engine lightSee what the light means →

Related symptoms: Car won't start · Rough idle or engine stalling

Check the fuse · If a light, the horn, wipers, a socket or the fuel pump is dead, a blown fuse may be the cause.Fuse boxes by car →

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

Book a diagnostic check

Questions

What does fault code B1681 mean?

PATS: transceiver signal not received. The immobiliser checks that the key is the right one. The computer didn't get proper confirmation from the key or immobiliser and may block the engine from starting.

Can I drive with code B1681?

Don't drive until the car has been checked. The engine could be damaged.

How much does it cost to fix B1681?

Roughly €60–600 in Estonia. The price depends on exactly what has failed and on the car.

How is B1681 fixed?

We read the immobiliser data with the diagnostic tool. We check the key and reader coil. We re-learn the key or repair the system.

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.