Multi Meters And Abs Sensors

[minijet]

It was originally my intention to run the 2.1 td until the MOT ran out then dismantle it for spares for the 2.0 turbo (not the engine of course), but I've decided that if I can get the ABS light to go out (it's been on constantly since I bought the car, six months ago), I'm willing to blow 50 quid on the off chance that it might just scrape through the MOT.

So, as my electrical knowledge - and equipment - are pretty basic................(my circuit tester)

........well, very basic........

...........I decided to splash out on one of these new fangled hi tech contraptions

Problem is, I haven't a clue how to use it.
First of all, there are two wires and three holes.
Second - there are twenty diferent positions for the dial in the middle.

So could some kind soul please tell me where to plug the wires in and where to set the dial.
I do know (I think) that there should be the same reading from all four ABS sensors, if one is different to the others, that's the one that's faulty (is that right?).

Also, I keep hearing about electrical contact cleaner, can anyone tell me where I can get some please - I looked in Maplins recently and they had about a dozen diferent types but they were all for pc's and domestic electrics - is there a particular type for auto electrics?

Thanks,

Paul.

[John Malkovich]

If you intend to check the ABS sensors, you will want to use the resistance range on your meter in the follwing way:

1. Siwtch the meter ON
2. Turn the dial to 2000 mark on OMEGA section (Ohm is a resistance unit)
3. Plug the black probe to COM hole
4. Plug the red hole to the middle hole, right above the COM hole
5. You should see 300 Ohm on each sensor if it is OK. A continuity (lower resistance) or open circuit (usually a "1" on display) indicate a bad sensor.

This post has been edited by John Malkovich on September 11, 2008 12:41 pm

[xmexclusive]

Hi Paul

Black probe lead plugs into the bottom hole that is marked earth. As you will most likely be measuring Voltage and Resistance the Red probe plugs into the the next hole up. To check out that the meter works switch the knob anti clockwise 3 clicks to the 20 volt setting and touch the meter probes on the car battery terminals. If you have the probes the wrong way round the display will show a reading somewhere around -12v, with the probes the right way round the - should disappear from the reading. You can now measure DC voltage and tell which is the earth side and which is the + side of the point you are measuring. It is good practice to switch the knob on the meter back to the OFF position when not using it or the internal battery will eventually go flat and add an extra problem to your fault finding. For resistance measurement as needed to check the ABS sensors turn the knob anticlockwise one click short of half a turn. To measure resistance it does not matter which way round the probe leads go as the measurement works either way round. As a check touch the tips of the two probes together and the meter should read zero ohms on the display. Leave the probe leads without contacting anything and you should get a resistance reading of infinity. You can now check fuses as a good fuse reads zero Ohms and a blown one reads infinity. Now hold the probes on the individual ABS sensor contacts in the Multi-plug that fixes to the ABS ECU to read the resistance reading of each of the four ABS sensors. Do not expect perfect rounded reading values just note down each one and look to see that they are all broadly similar.

The cleaner you want is a Switch cleaner. It just means that the fluid is formulated so neither the liquid or the residue when dry conduct electricity or are flammable so that it can be used on live equipment.

Regards

John

This post has been edited by xmexclusive on September 11, 2008 12:57 pm

[minijet]

Thank for the advice chaps, I'll have a go with it at the weekend.

Paul.

[Peter.N.]

Mine read about 2,500 ohms, different system?

[xmexclusive]

Hi Peter

Bendix early type are around 1100 ohms.
Bendix second type are around 2500 ohms.
Teves (marked ATE) are around 1200 ohms.
Teves20 do not know.
See self help file for range of permitted values for each type.

John

This post has been edited by xmexclusive on September 12, 2008 11:32 pm

[Peter.N.]

Thanks John.