ABS light - How do I diagnose it?

[Stevehall]

Hi everyone,

I've got the Bongo 2.5td out for the better weather, starting with an Mot. But my 4W ABS light coming on shortly after moving, and I think it has just been on from the start sometimes too. It was fine before being parked up last year!

Ive searched for the answers but there are so many conflicting ways, I'm quite unsure how to pursue with it! I have been using the philmcfadden connector descriptions and information .
I also watched a YouTube video of someone doing the TBS (N terminal) & earth link, and their abs light gave the flash codes? If I Link out the TBS pin (N) to earth, I just get 3 flashes, pause and then again 3 flashes over and over. The code 3 Doesn't mean anything, so I thought I would try the other way suggested using an LED... Firstly, can it be a bulb, as I don't have an LED, and secondly, which pins are they to be linked to? I would presume FBS and +B ? Do I have to do both ways to show the codes?

Update! The Bongo is a 1995 model.

Any help would be gratefully appreciated!

Thank You Steve

[g8dhe]

Are the 3 flashes all the same length, normally its long flashes (10's) followed by short flashes (units), which might be one long and two short which would indicate Left front sensor failing. Also make sure you are using the right pins, the Bongo has the socket mounted upside down compared to the diagrams!!!!

[Stevehall]

Yes, I noticed the the socket was upside down! I have checked to make sure I'm connecting the correct pins. I have now also made a test lead with an LED bulb to connect to the other way too, but I still only get 3 short flashes, no long ones? Im connecting to N in this diagram http://www.philmcfadden.co.uk/MazdaDiagnosticBox.htm to earth, then G to D with the led bulb lead.

I have also removed the heater assembly to check the connections on the ABS pump, they are good, and the pump works when powered up. I have read that the stop lights not working can be a problem, but they all light up, although the centre one is slightly dim.

Thank you Steve

[g8dhe]

N is the input signal to select ABS but the light/LED if it doesn't flash the ABS light as well is pin G;

N TBS Diagnostic-mode input (anti-lock brakes (ABS) control computer) - This needs an earth to trigger.
G FBS Trouble code output (anti-lock brakes (ABS) control computer) - also on some versions the ABS light itself on the dashboard.

[Stevehall]

N is the input signal to select ABS but the light/LED if it doesn't flash the ABS light as well is pin G;

N TBS Diagnostic-mode input (anti-lock brakes (ABS) control computer) - This needs an earth to trigger.
G FBS Trouble code output (anti-lock brakes (ABS) control computer) - also on some versions the ABS light itself on the dashboard.

I had connected the N TBS to earth but only got the 3 short flashes via the ABS light, I didn't have an LED in the lead. After this, I included a lead from G FBS to D 12v with an LED in, this time, I got 3 flashes from both the led and tha ABS light.

I just don't get it? I've checked and checked again, I'm sure I'm using the right pins.

What's the best way the check the speed sensors?

Thank you Steve.

[g8dhe]

A resistance check of the individual sensors would be best they are all around 1.6K Ohms.
Can't say I have heard any reports of just three flashes, its an early model as well so no chance of changes in the post 2001 versions affecting the codes.

[Stevehall]

Can't say I have heard any reports of just three flashes, its an early model as well so no chance of changes in the post 2001 versions affecting the codes.

It must be something I'm doing, so I thought it would be best to start somewhere else!

I will check the resistance on Monday and see what I find?

Thank you