1999 V70 T5 has had a replacement engine installed in 2018. After repair, the display panel would intermittently light up amber, including the periodic red illumination of the speed sensor. Speedometer would drop to zero, and the mileage indicator would be blank. The Volvo would continue to run fine. Also the cruise control no longer functions. We had a diagnostic done at one garage which indicated that the errors were all down to the speed sensor. At a nearby garage (without the computerised diagnostic tool) they contacted Volvo to order the speed sensor, but the regional Volvo dealership was unable to explain where the sensor was located. They claimed that for this model the speed sensor was on the wheel(s) and not on the transmission box. Our local garagist could see only the ABS cables. Can someone point me to a correct schematic or personal resource to get the answer: where is the speed sensor, and how to specify what needs to be replaced.

 

Instead of providing an answer to my questions above, as an alternative approach: Can anyone point me to a reliable resource for documentation (tech spec, repair and service manuals) for this 1999 V70 T5 manual transmission Volvo delivered in Europe? I've found a few paying documentation services, but not one yet that makes it easy to get to the documents. With the docs I could find the answers to my questions.

 

you can shop Amazon for a Haynes manual, you can find online manuals via subscriptions or you can buy the VIDA DICE CD on eBay (the OBD tool that works with the VIDA software is subscription also and quite expensive. The way these cars work is that the speed sensors are tied into the ABS - so they go from the wheels to the ABS controller,which in turn talks to the tranmission (for autos) and then on to the ECU. Its not uncommon for the wheel sensor to get nicked during repairs or grease from an axle boot tear (or engine repair) gets on the wheel which accumulates dirt. A quick fix may be to remove the wheel's speed sensor from the hub, spray the hub and sensor clean with some brake cleaner then see if that fixes the issue. Dunno if the manual transmission even has a speed sensor (can't think of a reason why it would)

 

MT6127 Thanks for the tips on documentation; I will follow up. As to the speed sensor on manual transmission V70, all I can describe are the symptoms: the speed indicator drops to zero and the mileage indicator goes to dashes, and a red indicator light goes on in the display, so you drive with no speed indication other than listening to the engine and transmission for a variable period of time... then it comes back, and all is fine. Not a great or safe way to drive. A local Volvo dealer also suggested that this model of the V70 had the speed sensor tied to the ABS, and only the automatic models had a separate speed sensor, but he couldn't confirm. You have. Thanks.

 

A follow-up thread to our Volvo V70 T5 1999 issues. Since the last thread in March, we have checked and replaced the ABS sensors on all four wheels of the car, with no improvements. The dashboard indicators for the ABS, the general engine indicator, the speed and mileage displays all have issues. With another garage here in France we have tried to pursue more diagnostics. The mechanic has succeeded in using three different diagnostic interfaces (TEXA, Bosch, Delphi) in communicating via the EOBD the motor management (calculateur gestion moteur) only, but not for the ABS or the CAN (?) which handles the dialogue between these systems -airbag, ABS, A/C). He cannot get past this blockage. It appears to be within these systems that a fault exists, and he can't isolate it.
Being an owner with no mechanical skills of use here, I'm frustrated to have the automobile unable to pass road worthiness tests, while the engine and the rest of the car behaves as expected. All suggestions welcome!

 

the abs wheel sensors feed into the ABS controller, which is known to develop cracks in the solder joints on the controller's circuit board. There are sites in the US that will repair the controller boards (Xemodex, Rocha-tek, Midwest ABS to name 3). check out those sites as they also have some good diagnostic tips on what symptoms can be traced back to the ABS controller. Note the ABS controller feeds the speed sensor info onward so it may explain other random faults.

 

Thanks MT6127 for the reply and suggestions. I will pass them on to the mechanic and translate for him.