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  1. #1
    Join Date
    Jan 2020
    Posts
    7

    Default Throttle Body Diagnose Help (xc 70 2004, 300km)

    Hello,

    I live in the Yukon, there is no mechanic around that is volvo familiar, so trying this first in case someone can guide me to fix my problem.

    Symptoms by order of appearance:

    Sporadically (once every other month specially on very cold weather below -20C) I'd get a reduce performance engine sign which would go away alone in a few minutes and never affect the driving, just the message on the car's panel.

    This summer I started getting more frequent Reduced P. Engine warnings but now the car would go occasionally on Limp mode. After restarting it would "fix itself". No codes, just the message with it's amber exclamation mark.

    Then I got rough idling (still no CEL) and poor acceleration (it makes sense if I do have a faulty throttle pedal position sensor) But It would go away after a few hours of not driving.

    Then eventually I got my first CEL and codes are:

    P0638 ECM-91A7 Throttle unit Faulty signal
    P0123 ECM-9150 Throttle unit, potentiometer 1 Signal too high
    P2135 ECM-903C Throttle position (TP) sensor


    What i've done:
    I cleaned the MAF with CRC and changed the filter when I thought it would fix the rough idling.
    When I finally got codes I cleaned the throttle body (to the best of my capacity), checked fuses (ok), and car runs ok but codes and symptoms come back randomly. Sometimes as soon as car reaches temperature, sometimes as soon as I accelerate over 70kph, I never know.
    Is it true I need the ECM to relearn that i've "cleaned" the throttle so the codes and symptoms would go away or am I miss-interpreting? eg: disconnecting black cable off battery.

    After reading a bit I guess my best move would be to get a new TP buuuuuuut, I'm still uncertain if this is the issue or I'm missing a more obvious DIY solution. I don't understand why the issue is intermittent, if a cable or connection or sensor are bad, wouldn't they always be broken?

    Could I be testing the TP sensor with a multimeter? If yes, how.

    I also got overwhelmed reading about "xemodex", orange label, white label Throttle body, VIDA, re-programming, not reprogramming... I feel like i wanna do all my homework but also I would appreciate so badly someone guiding me on the order of things.

    My scanner is a Foxwell NT301 so I'm pretty limited.

    Thank you all,
    brenda

  2. #2
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    584

    Default

    One nice thing about VIDA is it will give you steps to follow for each code thrown by your car's computer to help you diagnose what's actually causing the code and how to fix it. I haven't had throttle body issues (yet) so I don't have direct experience with your problem. If you're lucky, maybe you'll run into someone with a volvo who can diagnose your car with their VIDA/DiCE setup. It seems you're on the right track by cleaning the throttle body and MAF sensor (though some think it's not possible to adequately clean the MAF, only replace). You should also check for any leaking/disconnected vacuum hoses in the engine bay. It can't hurt to do a hard computer reset by tying the negative and positive battery cable ends together for an hour (you'll have to reset your clock and radio presets).
    If you don't get some responses on this site, try posting on swedespeed.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  3. #3
    Join Date
    Jan 2020
    Posts
    7

    Default

    Quote Originally Posted by Xfingers View Post
    One nice thing about VIDA is it will give you steps to follow for each code thrown by your car's computer to help you diagnose what's actually causing the code and how to fix it. I haven't had throttle body issues (yet) so I don't have direct experience with your problem. If you're lucky, maybe you'll run into someone with a volvo who can diagnose your car with their VIDA/DiCE setup. It seems you're on the right track by cleaning the throttle body and MAF sensor (though some think it's not possible to adequately clean the MAF, only replace). You should also check for any leaking/disconnected vacuum hoses in the engine bay. It can't hurt to do a hard computer reset by tying the negative and positive battery cable ends together for an hour (you'll have to reset your clock and radio presets).
    If you don't get some responses on this site, try posting on swedespeed.
    Thank you! Not to add a lot of drama but I live closer to the arctic circle than to anyone with a Volvo aaaaaand or vida/dice.
    i'll check swedespeed!

  4. #4
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    4,087

    Default

    The relearn isn’t needed, and disconnecting the battery on this car doesn’t really cause it to lose anything it learned, so don’t bother with that old wives tale. By the way, cleaning the MAF doesn’t really work, either. Get a new Bosch - genuine - not copy, not fake MAF.

    At 300,000 miles, there are a lot of possibilities. TB is certainly one of them. I would clean it and see where that gets you.

    Otherwise, spend it to XEMODEX- they did the TB on my 2001 T5. Works great. No programming needed. They fix yours and it’s plug and play.
    Current Fleet:
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    2002 V70-XC (275K, HPL Euro 0W30)
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    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

  5. #5
    Join Date
    Jan 2020
    Posts
    7

    Default

    Thank you Astro.

    I checked the xemodex site and for my model/year the only option they give me is buying a new contactless ETB but it does need recalibration/association with my car which I can't do given i don't own DICE/Vida (plus removing ECM and something else)

    I sent them an email see if they could work on my original TB like you said and hope this sheds some light.
    Also I see that is possible to do a DIY trick with some soldering and what not which I'm willing to try if they say they won't accept my TB.

    As for the MAF i assume it works since I don't get codes for it and bc when i disconnect it from the car running, the car stalls. I guess this is one rapid way to test, would have to find out voltage to give it a more thorough test?

    I'm basically down to buy a new TB and MAF but can't afford dealerships, reprogramming and sh*t bc i live quite literally in the middle of nowherre and have to do this on my own...

  6. #6
    Join Date
    Jan 2020
    Posts
    7

    Default

    alternatively, would you recommend this route?
    https://www.amazon.com/Bosch-0280750...productDetails

    it says plug and play but honestly at this point i dont know who to believe anymore...

  7. #7
    Join Date
    Jan 2009
    Location
    Sacramento, CA
    Posts
    164

    Default

    Quote Originally Posted by maraschino View Post
    alternatively, would you recommend this route?
    https://www.amazon.com/Bosch-0280750...productDetails

    it says plug and play but honestly at this point i dont know who to believe anymore...
    In the Q & A's and the ratings section the question of it needing programming was answered multiple times and it will not need programming but as one person mentioned the idle may be rough the first run then self-calibrates.
    In my car 2001 I don't have the Bosch throttle body although when I did replace the throttle body the idle was rough for a few minutes while it calibrated the idle speed and then was fine. If I clear all the codes with Vida or disconnect the battery it has to do the idle speed calibration once and then it's good. This if for a 2001 car with the Magneti Marelli TB so may be different than your car but it does sound it has a similar idle speed calibration routine so if you have a rough idle after replacing the throttle body just give a few minutes while idling and it should adjust. If you reuse the old throttle body gasket you may have permanent idle speed problems and other problems from an air leak so use a new gasket.

    You must replace the Volvo OEM throttle body gasket each time so don't do this job without a new gasket. The Fel-Pro gasket is very good and I've been able to reuse this gasket although not recommended, always use a new gasket. RockAuto has good prices on the Bosch MAF and throttle body and also carries the Fel-Pro TB gasket.

    from the Amazon Q & A section
    "I changed it on my 2004 and it's plug and play. You may have some bad idle or new code for the first run. Just clear code.
    By Pier-Luc Lacoste on September 12, 2018"

  8. #8
    Join Date
    Jan 2020
    Posts
    7

    Default

    Quote Originally Posted by FirstVolvo View Post
    In the Q & A's and the ratings section the question of it needing programming was answered multiple times and it will not need programming but as one person mentioned the idle may be rough the first run then self-calibrates.
    In my car 2001 I don't have the Bosch throttle body although when I did replace the throttle body the idle was rough for a few minutes while it calibrated the idle speed and then was fine. If I clear all the codes with Vida or disconnect the battery it has to do the idle speed calibration once and then it's good. This if for a 2001 car with the Magneti Marelli TB so may be different than your car but it does sound it has a similar idle speed calibration routine so if you have a rough idle after replacing the throttle body just give a few minutes while idling and it should adjust. If you reuse the old throttle body gasket you may have permanent idle speed problems and other problems from an air leak so use a new gasket.

    You must replace the Volvo OEM throttle body gasket each time so don't do this job without a new gasket. The Fel-Pro gasket is very good and I've been able to reuse this gasket although not recommended, always use a new gasket. RockAuto has good prices on the Bosch MAF and throttle body and also carries the Fel-Pro TB gasket.

    from the Amazon Q & A section
    "I changed it on my 2004 and it's plug and play. You may have some bad idle or new code for the first run. Just clear code.
    By Pier-Luc Lacoste on September 12, 2018"


    Thank you so much 🙏, I appreciate your time. I'll go ahead and buy the Bosch and gasket (rockauto) and recalibrate with patience. Glad I can avoid xemodex for now

  9. #9
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    584

    Default

    I'm not real familiar with throttle body issues but I'd also suggest taking a quick look for a possible leak in your vacuum lines and connections. Maybe other members have a better understanding, but if you've got a vacuum leak then replacing the TB and MAF may not solve your problem. Did you use a new gasket after removing and cleaning the throttle body?
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  10. #10
    Join Date
    Jan 2020
    Posts
    7

    Default

    Quote Originally Posted by Xfingers View Post
    I'm not real familiar with throttle body issues but I'd also suggest taking a quick look for a possible leak in your vacuum lines and connections. Maybe other members have a better understanding, but if you've got a vacuum leak then replacing the TB and MAF may not solve your problem. Did you use a new gasket after removing and cleaning the throttle body?
    I haven't done the smoke vacuum leak test, just checked visually as good as I could. If you know a DIY way to test this more thoroughly I'm all ears 🙏

    and i actually never removed the TB either, i cleaned it as good as i could in situ and it was indeed a nightmare and i know it's not how you're supposed to do it 100% right, and same with MAF i used CRC and I hear cleaning doesn't mean fixing, but now for example the car runs great even when reaches driving temperature and it throws no codes. Maybe the cleaning did help and getting the codes back soon after was bc I didn't know the car could have again rough idling after cleaning until the computer relearned it was all ok?


    My biggest issue is that I can't risk going out for longer trips like Whitehorse for example (500km from home), where there're more mechanics (it's already -20C here) and having this malfunction me on the klondyke highway, it's super risky and $$$ in every possible way.

    So after much research and forum help i think my best choice is to get a new BOSCH TB, new gasket and take it from there. And as for the MAF I won't buy it yet since the car stalls as soon as I unplug it, so i assume this is working OK.

    I'm still curious to check if the ECM ground connections are properly attached, I hear sometimes issues can be so dumb and easy (like fuses which i have checked) but in this case, being ignorant, i dont know which are the 10mm ground bolts of the ECM TCM... but hoping to do this test today.

    thank you for your time!

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