Interchangeable parts for transmission computer?

[Swedishcar]

Hello all
The ongoing challenge of my marriage to a1998 S70 turbo sedan ( married due to still paying on loan):
Now the check engine and flashing up arrow are lit up on my dashboard and it’s drivable but shifting badly.
My friend who is a mechanic has said it is the transmission computer and I have tracked one down but the model # is slightly different so I need to know if it’s compatible.
Old one: PO9181888
New one:PO9442488
Can I risk it? I gave the VIN and all pertinent info to parts place and that’s what they came up with as the correct part.
I can’t afford to take this to a Volvo place that will charge me $150. just to diagnose the issue. And the computer just slides into a slot; not difficult to install.

[scot850]

They both list for turbo as far as I can see. Yours lists as a 98-99 model and the references show it on EBay as for all 98 and 99 models. The other for a 98 turbo model and only lists for turbo. They have the same transmission, but maybe have different shift points for the different power curves.

Hopefully someone else can help. The Volvo dealer sites show both as not currently available so they have no details of what they fit. I will try to check on Vida later.

I don't know if it is still there, but there used to be a huge Volvo and Saab (I think they may now cover more brands) breakers yard near Sacramento. They used to be called vandsautodistmantlers.

Neil.

[abscate]

Are 1998 and 1999 TCUs the same? One runs Motronic 4.4 and a 99 runs ME7, pretty different …?

[Swedishcar]

Thank you , Neil, for your answer. I think the place you mentioned in Sacramento went under, as I called a couple of places there already. I lived in Sacramento for a while and loved that place in Rancho Cordova- kept my old brick running until I totaled it 5 years ago…
No luck on any other places and when I looked on A. and e, the prices were outrageous ( $100-400!)
I’m really tempted to try it for $50.

[matthew1]

My friend who is a mechanic has said it is the transmission computer

Can you expand on this a little? How did he get to that conclusion?

[misha]

First....you will need to read the codes from ecu end tcm(transmission ecu) to know what is going on.
In some cases...when tcm store a fault code,it will send a request to ecu to turn on CEL.

[scot850]

+1 to Matthews point. Why does your mechanic suggest the TCU is at fault? Has he pulled any codes to point to that?

Abscate also makes a very good point. There is a software change over in that time range. On the label the version should be printed on it for the software version installed on it.

Do you have any other lights on the dash like the ABS or Tracs/STC? If your ABS is on it could be the ABS module is failing or not getting a signal from the speed sensor. You could have a bad ABS sensor or tone ring or wiring to the module. If the ABS is not reading the speed the trans does not know when to shift and you will likely get rough shifting.

The vandsauto may have closed down, but there is another business in Rancho Cordoba that does not appear to have a website. It is called something like: Volvo, Saab, BMW, Mini Cooper Auto Dismantlers (VSBM). 3539 Recycle Rd, Rancho Cordova, CA 95742, United States. Phone number is : +1-916-635-9970.

Neil.

[Swedishcar]

Hi Neil and abate:
My mechanic had trouble pulling codes as his computer didn’t communicate well with Volvo but eventually he got a 666 code and a 411 the part- the transmission control module, a little box that just slides into a slot by the engine. I finally found one with the correct model number on eBay for about $40. Waiting on it in mail. Car seems drivable but feels like it is dragging that safe behind it so I’m not driving except necessities. I am hoping that installing it will not be a big deal but with this car…couldn’t find any posts with TCM or transmission control module in them but I will keep blundering on…

[Swedishcar]

That’s abscate

[scot850]

Are you sure the dragging issue is the trans and not the brakes? Could be separated parking brake shoes or stuck caliper.

Neil.