Brakes - Anti-lock braking and electronic control system

Information

This inspection applies to all systems whether original equipment, ‘optional’ or after market. 

ABS is a mandatory requirement on the following vehicles:

1	Motor vehicles with more than 8 passenger seats. And which do not have a load-sensing valve.	First used on or after 1 April 1983 to 20 May 2004
2	Motor vehicles with more than 8 passenger seats.	First used on or after 21 May 2004

Electronic Stability Control Systems are commonly referred to as ESC, but may also be known as ESP. The dashboard warning lamp for these systems may take various forms and a vehicle should only be failed when the examiner is certain that an illuminated lamp indicates an ESC malfunction. 

When testing vehicles that have ABS fitted the road wheels should not be allowed to rotate clear of the standing surface with the ignition on as this can cause the ABS system to indicate a fault which may require specialist equipment to rectify. If an ABS or ESC system has been intentionally rendered inoperative, the whole system must be removed. However, this does not apply to sensor rings or other ABS components which are an integral part of another component e.g. brake disc or drive shaft. In such cases a test drive should be carried out to ensure that there is no adverse effect to the roadworthiness of the vehicle. 

Note: It’s not permissible to remove or disable the ABS from a vehicle first used on or after 1 January 2010. Not all vehicles first used on or after 1 January 2010 will have ABS, so the failure only applies where the system has obviously been removed.

Method of inspection 

1. If the vehicle is fitted with an ABS or ESC system, check that a warning lamp: 

• is fitted 
• illuminates 
• does not indicate a fault 
• in the case of ABS only, follows the correct sequence of operation. 

Note: The sequence varies with the type of system. Refer to the manufacturer’s or other reliable data, e.g. purpose produced charts, books etc. 

2. Check the presence and condition of all visible ABS and ESC system components. 
3. Check the condition of all visible ABS and ESC system wiring. 
4. Check all ABS and ESC system components for any inappropriate repair or modification. 
5. Check the condition and operation of the switch (if fitted) to turn the ESC system on and off.

Reason for rejection

			Deficiency Category
1	The ABS or ESC warning lamp:	is missing	MAJOR
		does not illuminate	MAJOR
		does not follow the correct sequence of operation	MAJOR
		indicates a fault	MAJOR
2	An ABS or ESC system component obviously missing or excessively damaged.		MAJOR
3	ABS or ESC system wiring excessively damaged.		MAJOR
4	Any ABS or ESC system component inappropriately repaired or modified.		MAJOR
5	An ESC system switch insecure or faulty.		MAJOR