Engine computer and electrics

B1601 PATS: incorrect key code received

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

B1601 means: PATS: incorrect key code 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 most common repair costs about €90–180 in Estonia, depending on make and model. 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.

Key or immobiliser repair€90–180parts and labour in Estonia, depending on make and model

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 · Key or immobiliser repair €90–180
2Key reader coil around the ignition · Key or immobiliser repair €90–180
3Communication between immobiliser and engine computer · Control unit check and software €150–300
4Low battery voltage · Battery replacement €120–220

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 Received Incorrect Key-Code From Ignition Key Transponder

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 B1601 mean?

PATS: incorrect key code 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 B1601?

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

How much does it cost to fix B1601?

It depends on the cause: key or immobiliser repair €90–180; control unit check and software €150–300. Prices include labour at €45/h, depending on make and model.

How is B1601 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.