2007 Toyota Alphard brake issue

[Wozzer100uk]

Hi all,

I really need some advice on the issue I'm having with the brakes locking on my 2007 Toyota Alphard. Last week when i went out for a drive the speedo stopped working but the van seemed fine to drive apart from that. I hooked up my fault code reader and it came back with a Speed sensor fault, i looked online and the cause for this as the speedo wasn't working was most likely the KPH to MPH conversion chip that is fitted as the van is from Japan. So had the chip replaced and test drove it and the speedo came to life but then i noticed the brake pedal got very stiff and both front brakes ended up completely locking on. 2 hours later and a few more chips it was decided that it was the transmission speed sensors that were at fault . The guys managed to disconnect them and then i manged to drive for a short time before they locked up again, i was very close to home so slowly drove back, my brakes actually started to smoke because they got so hot!. Yesterday at home , i had both the speed sensors on the transmission replaced, took it for a drive for 5 mins and all seemed well . Got it back home then went back out to get my brakes looked at to make sure they were ok after getting so hot and no more than a mile down the road they locked again and i was stuck on the side of the road. Its automatic and the gears do go funny not shifting correctly but i think that maybe to do with the brakes locking on.

So far I have spent £450 and the issue is actually worse than before i started! I've been advise my the garage i bought it from to take it to a specialist to diagnose but will have to pay a lot to get it towed there. I now have no fault codes and the speedo is working its just the brake issue. Can it be just a coincidence that after i fixed the speedo a fault on the brakes developed? Are there any tricks for me to do that can pin point the cause , like it being the brake booster, or something else? Do i need a general mechanic or specialist ecu person?

I would appreciate any advice on this. Cheers

 

[carmanmemoranda]

There's a lot of mixed up stuff in there.

Brakes locking on sounds a mechanical issue not electronics.

You need to check the calipers, sliders and pads are moving freely or not 1st.

Speed sensor issue could easily be an abs issue.

 

[Harry Bloomfield]

So far I have spent £450 and the issue is actually worse than before i started! I've been advise my the garage i bought it from to take it to a specialist to diagnose but will have to pay a lot to get it towed there.

If you bought it recently, then take it back to the garage you bought it from, and get them to fix it - and free of cost to you..

Are there any tricks for me to do that can pin point the cause , like it being the brake booster, or something else? Do i need a general mechanic or specialist ecu person?

You need a specialist, a really good autoelectrician, to investigate your electronic issues, and probably a mechanic to investigate the brakes.

To be honest, you tale of woe, sounds really confused. It is not usual to 'change a chip' to swap from kph, to mph. Normally it would be a matter of changing an option in the software, changing software flag, simply by plugging a gadget into the car.

Usually the speedo is driven by pulses, from a wheel, a sensor also used for the ABS system.

The brakes locking on, don't sound as if they are are associated to your other issues. More likely that might be due to seized calipers.

 

[Wozzer100uk]

Thanks guys, yeah i know its a lot of stuff. Its messed my head up! From what i know, most of the Alphard's imported have the chip to change from KPH to MPH.

I will take your advice and get it to a local mechanic to look at the breaks then see how i get on from there. Just so odd that it all started from the speedo not working and when that gets fixed the breaks have an issue. There has been no ABS light on the dash and now now faults reading from the OBD2 reader. The van is 2 years old so no longer under warranty.

 

[Mottie]

There's a lot of mixed up stuff in there.

Brakes locking on sounds a mechanical issue not electronics.


Speed sensor issue could easily be an abs issue.

I had the same problem once when I fitted a pattern part wheel bearing (containing the ABS trigger) to an automatic Mondeo. Fitting a genuine Ford one cured it instantly.