Speedo and Tacho not working 2005 Alphard Petrol Auto

[Selky]

Hi there , wonder if anyone out there can help . I have a 2005 Alphard Petro l Auto ( 2.4) . The speedo and rev counter dials stopped working(rest is fine , including the mileage ) .  I have tried multiple garages and no-one seems to know how to resolve this. The van is otherwise working fine .  I even tried to source a replacement Dash as a last resort from Japan , but was unable to find a source.. Appreciate any help/advice on this one 

 

cheers 

Dave 

[Rojie]

4 hours ago, Selky said:

Hi there , wonder if anyone out there can help . I have a 2005 Alphard Petro l Auto ( 2.4) . The speedo and rev counter dials stopped working(rest is fine , including the mileage ) .  I have tried multiple garages and no-one seems to know how to resolve this. The van is otherwise working fine .  I even tried to source a replacement Dash as a last resort from Japan , but was unable to find a source.. Appreciate any help/advice on this one 

 

cheers 

Dave 

 

Hello Dave,

 

Welcome to the Forum.

[Catweazle]

Could be a few things obviously....try plugging a cheap OBD reader into the plug below the steering wheel to see what error codes are present.

Check that there are no loose connections from the sensors under the bonnet below air filter. My speedo wasn't working once, and replaced the speedo sensor on the gearbox and it fixed.

Could be the speedo convertor chip behind the main binacle...again, I gave my convertor chip connections a check and found them loose.

[Geralt]

It's unlikely that the motors for both tacho and speedo have broken at the same time. It's a little more likely that there's some internal common motor drive power supply problem.

Much more likely is that you have a dodgy connector disrupting the TAC+ and SI input signals as shown in this post:

 

But, if so, you should also see a P0500, Vehicle Speed Sensor DTC which you should confirm with an OBD reader.

 

@Wisey Was your tacho working when you had a similar problem? What was your fix in the end please?

[Wisey]

3 hours ago, Geralt said:

It's unlikely that the motors for both tacho and speedo have broken at the same time. It's a little more likely that there's some internal common motor drive power supply problem.

Much more likely is that you have a dodgy connector disrupting the TAC+ and SI input signals as shown in this post:

 

But, if so, you should also see a P0500, Vehicle Speed Sensor DTC which you should confirm with an OBD reader.

 

@Wisey Was your tacho working when you had a similar problem? What was your fix in the end please?

The tacho didn’t stop working, only the speedo. I found the problem to be the retrofit chip by completely removing it and reconnecting the wires, the speedo then worked perfectly well but in Kph. 
I decided to leave it that way and used the power supply to the chip to fit a USB socket beside the binnacle and connected a neat little GPS digital speedo on the steering column to read in Mph. Perfect!

I can let you have some photos if I knew how to download them (URL?)

Hope this helps,

Alan

[Geralt]

Thanks for coming back with the root cause and solution, good to know.

I suppose that means Selky's problem is going to have a different cause becuse his tacho isn't working also.