NEED ADVICE ON MY S70 2.0T 5 SPEED YR 2000.

[IAS-S70]

Hello guys…
Needs some advice and opinion regarding my Volvo.
I don’t know what’s going wrong with my S70 2.0T 5spd auto tranny (mileage 140K km).

This is the chronology what happen to my car for the past 2 months.
1. On the way back from office, from smooth gear changing from 1st to 5th gear before, my car transmission going crazy. Just change from 1st and 2nd gear only. When I shut down the engine about 30 sec and restart back everything is ok and back to normal but after 2-5 min driving the transmission going crazy.
2. For the next day, I was send my car to FA (Volvo authorized 3S) for diagnose and found code P1618 means my solenoid no 2 permanent fault. Than my mechanic test drive my car and push many times on/off winter mode button and the transmission back to normal.
3. Run diagnose again and found code P1618 solenoid no. 2 intermediate fault (LOL the fault can downgrade). My mechanic cleans all electrical connector which related to auto tranny. After that, everything looks fine.
4. After 2 or 3 weeks, other problems come out. During accelerate, the gear change from 1st to 5th is too fast and not follow the RPM meter, just imagine at speed 40-60km/h run at 5th gear. When slow down to stop my car the engine vibrate and died at traffic light. Looks like slowly brake and stop the car with manual transmission at 5th gear but forgot to press clutch lever. After restart back the engine, everything is back to normal.
5. The funny things are the problem was happen once a week. This crazy thing happens on every Saturday night… Ha..ha..ha… The rest of the day nothing’s wrong with my car.
6. Last few days, I was send my car for full car diagnose at Volvo Cars and don’t see any fault code appear unless faulty code P0237 Generic turbo/super boost sensor A circuit Low Input and P0236 Generic turbo/super boost sensor A CKT range. I don’t see any transmission fault code like P1618 appeared. P1618 code gone already.
7. I am also clean the MAF sensor located at air filter with Contact Cleaner but never touch it. Last Saturday 27th Feb 2010 as usual, this problem happen again. I just told my mechanic but they don’t have any idea how to resolve this problem.
8. Before all this problem appeared (1-7), 3 months ago I was installed full set of ABM headlight + HID light. My mechanic was put the HID ballast inside the ECU and TCU box. I am worried if the heat from ballast device will affect the ECU and TCU. Last month I was dismantle the ballast device and put it at new location somewhere inside car’s bumper.

Please guys; I am really needed your advice and opinion how to resolve this problem. Thanks.

[Ozark Lee]

I would start by cleaning the edge connectors on the ECU and TCU with contact cleaner. The TCU gets quite indecisive when it is not seeing proper voltage. In some cases it can get quite decisive but make the wrong decisions.

When was the last transmission fluid change? The Volvo fluid is stupid expensive (JWS-3309) but I have heard that you can buy the same formulation from Toyota for much less - just make sure it states JWS-3309 on the label. Two or three drain and fills on the transmission fluid can make a world of difference.

...Lee

[IAS-S70]

Dear Ozark Lee,

Thanks for your reply. I just changed/flush transmission fluid with Toyota T-IV which meet JWS3309 for past 2 month ago (mileage at 132,800km). I am agree with you that The Volvo ATF is stupid expensive. If don’t mind, do you have any idea how to dismantle TCU and ECU? I don’t know how to take out the ECU and TCU. Is it necessary to check Vehicle Speed Sensor?
Thanks.

[Ozark Lee]

On an 850 I could tell you exactly how to remove the modules but on the S/V series I think there is some kind of strap that you need to remove to get to them and I'm not sure how it is removed. Once you get the top off of the computer box it is simply a matter of lifting the levers to remove them (the ECU and TCU). I would disconnect the battery cable before messing with anything at this level. You will, of course, need to have your radio code once you hook the battery back up.

I know MIJ has done this and I think BEJinFBK has as well, hopefully one of them will jump in and give you more hands on expert guidance.

...Lee

[IAS-S70]

Dear Ozark Lee,

Your advice and opinion regarding this matter is highly appreciated. Hopefully MIJ and BEJinFB will help me with expert guidance.
Thanks.

[badcadman]

I just finished up swapping a new engine & harness into my '99 S70 and had to dismantle the computer/trans connector.

Here's what I did: remove the top cover for the computer housing. There will be 2 bolts that secure the plastic center housing that the top cover snaps down to, remove those and unsnap the center housing from the bottom housing. With the center housing removed you have easy access to the retainers that hold the computer in the connector. Take a long screwdriver and move the keys (they were a purple color on my car) towards the front of the car. This should release the computers from the connectors. Naturally make sure your battery is disconnected and you have discharged any static electricity from yourself before you handle the computers. Good luck!

[IAS-S70]

Dear badcadman,

Thanks for your tips. Try to do it and hopefully will solve my problem.

[iforparry]

Hey badcadman, thanks for the ECU removal tips. Been searching days for this. I attempted today to no avail. After I put everything back together (unsuccessful removal) I got the dreaded flashing arrow with P codes 0236, 0237 & 0722 with my OBDll reader. Need a new booster sensor which I ordered today. I don't have a replacement TCU but picked up an identical ECU to mine cheap. With these instructions I should be able to do it in the morning. Thanks a million!!

[badcadman]

Glad to be of help.