Difference between revisions of "Handbrake And ABS Warning Light Troubleshooting"

Latest revision as of 20:13, 20 February 2011

Overview Guide
Ford Model:	Mondeo
Petrol/Diesel:	???
Estimated Cost:	???
Difficulty?	???
How long does this take?	???
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Handbrake

Hand break pulls up but wont lock the rear wheels? check the back break pads are not worn down.

Handbrake Light Troubleshooting

Problem

Handbrake Light Permanently On

Solutions

The brake fluid level may be low The level sensor and/or connector and/or wiring may be faulty. The pressure in the system may be low. These symptoms will also turn on the ABS light. Alternatively, the handbrake switch may be faulty or sticking. Check and WD40 it via the coin holder hole near the handbrake.

Problem

Handbrake Light Permanently Off

Solution

The light bulb in the instrumental cluster may be blown The handbrake switch may be clogged with dirt. Check and WD40 it via the coin holder hole near the handbrake. (spray - then use a long screwdriver to work the switch)

The ABS Light Stays On

Solutions

This is a fairly complicated technology and there can be many different reasons why the light comes on when it shouldn't. It is worth noting that Meggers who have paid out hundreds of pounds for a new ABS module/pump have found that this has NOT fixed the problem... even when Ford has charged nearly £1000! It should also be noted that when the ABS light comes on, that the conventional brakes still work - assuming that the normal parts are in working order

The first checks to make are the ABS related fuses in both fuseboxes and the relays. Then check brake fluid level/switch/wiring. The next most likely cause of problems is one or more faulty wheel sensors/wiring/connectors. The front connectors are in the front wheel arches, and the rear connectors are under the rear seat.

Using digital test meter you can check for continuity. Also, if switched to a 3 or 10 volts AC range and connected to both sensor leads/wires, when the wheel is spun by hand, you should see some voltage output if sensor is OK. If not then take sensor off the hub and wave a small magnet close to its end. Should again see some indication on meter... depending on the quality of the meter! Clean connectors, repair wiring or replace sensor as required. Often, the ABS sensor can be stuck in the plate or drum. Do not use excessive force to remove the ABS sensor as you will damage it. Scrap yards often supply the whole knuckle/hub/sensor assembly as they cannot remove the sensor.

In use, the sensor works by the rotation of the nearby toothed "ring" mounted on the hub assembly. If the teeth have broken or some of them are missing, then you have to replace the hub. Also this (aluminium) ring may have cracked so that it is no longer a complete solid ring. If so replace hub. Some Meggers have reported that the teeth can become clogged with conductive muck/mud/salt which also stops the sensor working and brings up the ABS light. A thourough wash and brush up should cure things in that instance. With rear drum brakes, the sensor ring is *inside* the brakedrum. Brake disks, drums and hubs can be a pig to remove without big hammers and the expertise!!! More on that in the forums!

Thats the end of the "easy checks", We are getting into expert checks next ...which many people may prefer to pay technicians to carry out!!

YES, you can get frauds or someone with a diagnostic tester to connect up and readout the ABS fault codes. For some strange reason, "Faulty ABS module/pump" always apparently appears ...and at £5/600 at time is a good earner for someone!

Alternatively, you could check out the various connectors and looms, then the vacuum pipes for leaks ... and then make doubly sure that all the hydraulic, servo, pads, shoes, drums, disks, caliphers, wheel cylinders and master cylinder and all pipes/tubing and joints are in proper working condition.

It should be noted that for MOT purposes the ABS must be properly functioning and the light should go out after 3 seconds on starting the engine.

NOTE. You can remove the ABS system from the car altogether if reverted correctly to a normal system ...which requires time labour and some replacement hydraulic parts. This apparently costs about £200 to have done as posted in the forum somewhere.

Brake pad/shoe wear indicators

As far as I can see, the only thing that actually uses these is the brake wear warning light on the AWS (auxilliary warning panel) or trip computer if you have either of them and the various other bits actually fitted in your car. So for many people with ABS probs, checking the brake wear wiring and connections is a waste of time. CHECKING THE PADS/SHOES IS A MUST DO!!!

Disclaimer

Your car/vehicle brakes and system are crucial. If you have no idea or expertise in this area...then take your car to somewhere relevant to have the job done, or get a mobile expert in a van to visit. MEG can accept no responsibility for the well-being of you or your car.