No tachometer and spedometer 1998 Volvo S70 Topic is solved

[WinDVD]

There is a speed sensor on the transmission. I can't recall how it works on the 1998 and older model. DDM as Abscate mentions could be an issue.

Do you know if the dash top has been removed at all? I had issues with my 00 V70 at one point and eventually discovered at some point someone had it apart and not refitted the connector on the back of the unit correctly so it was loose.

Neil.

It's possible it's been removed, but I'm not certain. the previous owner mentioned they had used this car as a parts car for some interior parts and later decided to fix the car instead. It's also possible they took a good cluster out and put a bad one in.

[abscate]

I had a quick look on the circuit page but the tach gauge is driven by the central display module CPU

[WinDVD]

I had a quick look on the circuit page but the tach gauge is driven by the central display module CPU

Ahhh, I see, Do you think the CPU is faulty? Or is it possible there's just cracked solder joints/bad caps? Is this a common issue?
I just mainly want to know if it's repairable or if I will need to buy a new cluster lol

[abscate]

I’ve never dived into a driver display module or central display module ( I’m not sure what the official name is)

This is what you get in VIDA on the 99 v70, the 98 might be a bit different

I’m not sure where engine speed is fed into the display processor, somewhere on the left

[WinDVD]

I’ve never dived into a driver display module or central display module ( I’m not sure what the official name is)

This is what you get in VIDA on the 99 v70, the 98 might be a bit different

I’m not sure where engine speed is fed into the display processor, somewhere on the left

I managed to find a 98 specific one, from what i gather A3 is speedo input and A11 is tach input
Considering fuel and temp are working, It would be surprising if the CPU failed, I'm thinking maybe there are some bad connections somewhere.

I'll dig out the cluster when I get the replacement bulbs in the mail on Monday. Thanks for all the help, I'll keep y'all updated

[xanthefin]

If you end up opening the gauge cluster there is at top left "Yazaki" chip it might need reflow soldering as even it not being the brain OBD might still affected by it too as the K line chip (or actually just some totally not K line com chip which been used as one as Volvo did during this period -i forgot what it was in reality) has connections to it too as due OBD being silent too so throwing just as what i would do as first. Yazaki chip is mostly for being LCD driver etc. all controller chip.. the big brain is next to ODOmeter at more bottom.

[WinDVD]

If you end up opening the gauge cluster there is at top left "Yazaki" chip it might need reflow soldering as even it not being the brain OBD might still affected by it too as the K line chip (or actually just some totally not K line com chip which been used as one as Volvo did during this period -i forgot what it was in reality) has connections to it too as due OBD being silent too so throwing just as what i would do as first. Yazaki chip is mostly for being LCD driver etc. all controller chip.. the big brain is next to ODOmeter at more bottom.

I see, Thanks for that, I'll look for it when I take it apart and see if I find anything damning, I hope the issue is actually in the cluster and not some weird wiring fault.

Maybe I'll be lucky and it's just needing connectors reseated lol

[Chili58]

Is your car with automatic or manual gears?
That year is difficult because of changes in softwares; can you give the VIN number to see correct version.

[WinDVD]

Is your car with automatic or manual gears?
That year is difficult because of changes in softwares; can you give the VIN number to see correct version.

It is a manual car, VIN is YV1LS5540W1497077

[Chili58]

I understand you purchased a car, that had all the issues. Therefore it is good to check - at least - that the ABS control unit is a correct one; you never know, if the previous owner swapped there a wrong ABS control unit already.

The correct ABS control units are any of the following ones in case you have also TRACS : 9162675, 9140774, 8602266 ; but you should be sure about the fact, if you have TRACS or not.

But Volvo part # 9140773, 8602265 are correct ones for vehicles WITHOUT TRACS traction control. Both part numbers are identical/compatible.