Seat belt diagnostics and checks

Inspection and verification

1. Check the validity of the customer's complaint by activating the system.

2. Perform a visual check for obvious signs of mechanical and electrical damage.

Visual Inspection Table

Mechanical factors	Electrical Factors
– Loose Tape – Damaged/worn belt – Seat belt retractor and tongue assembly – Retraction mechanism – Pyrotechnic tensioner lock	– Indicator lamp - Chain – Central timer module

3. If an obvious cause for a noted or received complaint is found, troubleshoot (if possible) before moving on to the next step.

4. If the cause of the problem is not obvious, check the symptom and refer to the Troubleshooting Table.

Trouble symptom table

State	Possible Causes	Action
•Normal mode - The vehicle occupant safety system is not working	• Broken tooth of the gear wheel of the sensor of the retraction mechanism. • Loose tape.	• REFER to the Function Test in this section.

Function test

WARNING: In the event of an accident in which the airbags deploy, all seat belts in use at the time of the accident must be removed; you need to install new seat belts. Failure to follow this instruction may result in personal injury and component failure.

Bad retraction

If the seat belt does not retract correctly, check that the anchorage covers and decorative trim are installed correctly and that these items do not rub against the seat belt webbing. If necessary, check that the seat belt webbing is not rubbing one edge against the opening of the retractor cover and, if this occurs, correct this condition by loosening the mounting bolt and aligning the retractor so that the seat belt webbing is centered. Then tighten the bolt again.


Focus vehicles are equipped with two front and three rear inertia reel seat belts. These seat belts are "dual sensitivity". This means that the belts have:

• a vehicle motion sensor that blocks the seat belt during braking, turning, sharp uphill and downhill runs and sharp bends in the roadway.
• belt motion sensor, which is blocked when the seat belt belt is quickly pulled out.

Both systems must be fully operational. They can be verified using the following checks:

Vehicle Motion Sensor Test

Either of the following two procedures can be used to verify that the vehicle motion sensor is functioning properly. Both methods require the participation of two mechanics, however, please note that these checks should not be left to mechanics with a larger than normal build to perform these checks. This is necessary so that full unwinding of the seat belt webbing is not mistaken for proper locking provided by the seat belt retractor mechanism.

1st way to check (braking)

WARNING: It is important that during this test, seat belt occupants give the seat belts a chance to secure and do not try to anticipate a sudden deceleration. The steering wheel should not be used as a prop. However, both the driver and passenger must be prepared for the possibility that the seat belt will become blocked. The passenger should extend their arms in front of them towards the instrument panel or front seat backrest (depending on which seat belt is being tested). Failure to follow these guidelines may result in injury.

• Choose a quiet stretch of road or a private road for this test. Make sure the road is clear and you have a clear view at all times.
• The driver and passenger should adopt normal, comfortable seated postures. Both occupants of the vehicle must fasten their seat belts, and the seat belt webbing must be correctly adjusted without slack.
• Drive at a speed of 10 km/h (6 mph). Do not exceed 10 km/h during this test (6 mph).
• Depress the brake pedal sharply to stop the vehicle. If the motion-sensing locking mechanism is functioning properly, the seat belt webbing will lock and hold the seat belt occupant.
• Check twice for each front and rear passenger seat.
• Any seat belt retractor that does not restrain the occupant during this test must not be used. A new seat belt needs to be installed.

2nd way to check (turning circle)

This test requires a level, open area of the road, sufficient to continuously drive the vehicle in a circle in the full position of the steering wheel.

• The driver must fasten the specified seat belt, and the seat belt strap must be correctly adjusted without slack.
• The passenger must sit in the back seat, and the seat belt must be correctly adjusted.
• Start the engine and, turning the steering wheel to the rightmost lock position, drive continuously in a circle at a speed of 16 km/h (10 mph). When performing this test, do not exceed the speed limit of 16 km/h (10 mph).
• At a steady speed, the passenger should attempt to slowly pull the seat belt webbing out of each seat belt retractor in sequence. If the locking mechanism, which is sensitive to the movement of the vehicle, is functioning properly, the tape cannot be pulled out.
• Any seat belt retractor that allows the tape to be pulled out during this test must not be used. A new seat belt needs to be installed.

Checking the elements

With the vehicle stationary on a level surface, firmly grasp the seat belt webbing (on the side of the tongue of the upper element of the seat belt anchorage) and quickly pull the tape out. The retractor should lock at 0.25 meters (10 inches), preventing further stretching of the tape. Any seat belt retractor that allows further retraction of the belt must not be used. A new seat belt needs to be installed.