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GM's triplets Venture, Silhouette, and Montana



  • CapeCodCapeCod Posts: 117
    My wifes Olds Silh 1998 has had a SES light come on.
    Code was read at Advance Auto.... oxygen sensor bank 1, etc...
    I reset the code. things seemed fine.
    My wife claims she hit a pothole and the Service Engine light is back on.
    My questions:

    #1 Since the van is running fine, could the light have been triggered by mileage??
    the Van just passed 105,000 miles.... coincidence ??? or factory preset ???

    #2 Could the 'pothole' jar a loose wire ??? Wet ???

    #3 Online I see downstream? upstream? sensors explain???
    Parts are usually $75 range... What should I figure for labor ???

    Thanks :)
  • It could be any one of about 75 different sensors. Difficult to diagnose, even for a highly trained technician. I solved a similar problem on my 1999 Montana by disconnecting the battery cable, then reconnecting it. That seemed to clear the code problem for about a year. This model van seems to have lots of "mystery" code problems that my dealer can never trace to a specific problem. They want to start replacing parts (guessing) and see if it solves the problem!
    Jack in Colorado
  • 442dude442dude Posts: 373
    Can you post the actual codes they got instead of what they said was the problem? Sometimes you have to be smarter than the car and deduce what the problem is based upon multiple codes.

    For example - Check engine light lit - I got multiple codes (don't remember them now) that pointed me towards:

    -MAF sensor
    -O2 sensor
    -idle air control
    -high idle speed

    apparently there was an air flow problem in the engine....

    Solution - pcv valve was stuck open and was allowing too much air flow at idle, for
    $ 3.00 I replaced it and haven't had a problem since...
  • CapeCodCapeCod Posts: 117
    Code was P0135 02 heater circuit malfunction...
    I cleared code and the same code came back....
    From other postings here and on other sites....
    taking it to the garage will be a 'gamble'....
    Some got $60 first time fixes... others $1000 with light still on!
    Once the weather improves I may try to check wire harness ????
    Van runs too well for anything serious to be wrong ????
  • 442dude442dude Posts: 373
    PO135 bank 1 is the sensor before the cat converter - here's my thoughts:

    since the light came back after you hit a bump, I would check the connector first, make sure the connector is clean on the inside and that the wire/connector is not damaged. If it all looks OK I would start to suspect the sensor itself. After 105K miles, it may be shot and need to be replaced. I'll check the diagram when I get home, if you've got a multimeter we can check to see if its getting power and see if its sending voltage to the ECU. I'll repost later...I'm thinking the O2 sensor is shot...
  • 442dude442dude Posts: 373
    First a disclaimer:

    I'm not a mechanic and I don't play one on TV, I'm just a shadetree mechanic who likes to play with and fix cars. If you don't feel comfortable with doing these checks, leave them to someone who does. I can't take credit or blame if this goes good or bad. I've done my best to make sure that what I typed was right... You're on your own...but if you decide to tackle it, here's some guidelines. Please read them all first before you try anything...Please! I don't want to see you get hurt or mess up your car! Also, be sure to use a digital multimeter as O2 sensors are very sensitive and an analog one will destroy an otherwise good O2 sensor. And one more thing - all of these sensors use really low DC voltages to do their job so be sure that the connectors are in good shape and that you're careful with them when plugging them and unplugging.

    For some of these checks,you'll need to backprobe the sensor connector with jumper wires or "t-pins" - And of course, you'll need a multimeter...

    First - check the resistance of the O2 sensor heater. Since your code indicates trouble with the O2 sensor heater circuit, you may find your problem right here. Disconnect the connector and probe the connector on the sensor pigtail with the multimeter set at ohms of resistance. Connect the pos & neg of your multimeter to the pins that are top and bottom right as you look into the connector with the clip at the top. They're usually white wires. You should get resistance between 3 - 10 ohms. If you get an open circuit or excessive resistance, the heater is bad and you have to replace the sensor.

    2 If that checks out OK, reconnect the sensor and lets check the signal to the sensor (this will set a check engine light which you can reset later) by backprobing, connect the multimeter positive to the purple (or purple/white) wire and the neg to the tan (or tan/white) turn the ignition on but do not start the car. You should get approx 400 to 450 millivolts. If you don't, check your wiring to the PCM.

    3. Check for sensor operation - start the engine and let it warm up to operating temp. Check your multimeter again. It should now range between 100 - 900 millivolts. and switch between a high and low reading in that range. If it doesn't - it needs to be replaced.

    4. Check the battery voltage to the sensor - shut engine/ignition off and disconnect the connector from the sensor pigtail. On the harness side of the connector - Connect the neg of your multimeter to the corresponding terminal for the black wire ( should be top left as your looking into the connector with the clip at the top) and connect the positive to the corresponding post for the pink wire (should be bottom left)
    Turn the ignition on but don't start it - you should get about 12 volts. If you don't get 12 volts, you've got a wiring issue...and don't forget to check the fuse as well. IF the fuse is blown for the O2 sensor you'll set a code as a matter of fact, check the fuse before you do anything, you might save yourself a lot of work.

    To clear the trouble codes you've generated, just disconnect the battery for a few minutes and then reconnect. Best of luck - hope I helped you.
  • 442dude442dude Posts: 373
    How did you ever make out with this??? My guess is: bad O2 sensor or blown O2 sensor heater fuse....Just wondering...hope I was able to help you.
  • CapeCodCapeCod Posts: 117
    Cold weather....
    are my excuses for not going to a garage yet....
    Real reason...
    I just don't trust my mechanic!
    Blown heater fuse ????
    That's a new one....
    Is there a fuse under dash? Replace? Reset???
    Car runs so well... I hate to start throwing $$$ away.
  • 442dude442dude Posts: 373
    The O2 sensor heater has a fuse - should be in the underhood fuse block...if its blown you'll need to replace it - its one of those blade fuses - 2 in case the 1st one you put in blows right away...

    On the bright side, the heater only brings the sensor up to temp sooner so it will start working quicker. The old ones were unheated and just waited for the exhaust heat to warm them up to operating temperature. If you decide to let it ride for a while the only disadvantage is that you stay in open loop mode for a few more minutes while the exhaust warms up the sensor and then all is well and the sensor is most likely working normally . Its probably why you haven't noticed any difference in the way the car runs. If you're running good and the fuse checks OK, wait until the spring, change the O2 sensor yourself (not a hard job-part will be under $ 100) and I bet your problem will be cured... best of luck
  • Just a little heads up to those who may not know....
    We recently had a problem with check engine light coming on. Code read said it was an O 2 sensor so we replaced it and it kept happening. We changed it 3 times with an after market sensor from 2 different parts houses and come to find out some of the after market sensors will not work on the Montana. We bought a dealer part O2 sensor and have had no problems for the last year. Strange but true. Also we have had the worst luck with the Ac condenser. Replaced 4 times this past summer and it works fine for a few days then when we crank the car you will hear a loud popping noise then the air goes back to hot. We were told it was probably bad parts but lets get real four times uhhhhhh don't think so ! Is there maybe something to do with to much pressure building up and causing the condenser to blow. Our vents don't change when you turn the knob either. I can hear it blowing but not out of the vents. I would love nothing more than to sell tickets and let my neighbors watch me blow this van up! I hate this thing. Don't even get me started about the head gasket leaking because if one more person tells me its normal I will be wearing a jumpsuit!!
    Figuratively speaking of course I would be grateful for any feed back.
  • 442dude442dude Posts: 373
    I can't help you with the O2 sensor issue - I have used aftermarket O2 sensors for years without a problem...

    I also can't help you with the head gasket - the usual issue with the 3.4L V6 is the intake manifold gasket, not the head gasket so I'm not sure what's going on there.

    AC condenser popping...?????

    As for the vents not switching, they are switched by engine vacuum. There's a hose that runs from the dash actuator which goes along the passenger side footwell and through the firewall. It then loops around the windshield washer tank and hooks to a vacuum port just above the accessory drive belt. Check to make sure that its attached on both ends. My hose became plugged so I had to run a new one...not a hard job. I'd bet that your problem is similar, either the hose fell off or its plugged/broken...hopefully someone can help you with the other stuff...
  • tro15tro15 Posts: 1
    I found a BRAND NEW wiper motor on E-Bay for 75 bucks and 8 s&h. Good deal since most boneyards wanter 50 to 100 dollars.
    I am going to try and replace it myself, looks easy enough. the only hard part is getting the large trim panel off the rear hatch.
  • snowman89snowman89 Posts: 36
    I have an 01 venture lt and it's not aging well. With 93000 miles I have had some pretty expensive repairs in the past 18 months. First was the a/c condensor at $500, next the front wheel bearings and new brakes all around which topped out near $800, and just this week I fell victim to the cursed PCS in the transmission which when combined with a full flush and service of the transmission fluid came to a total of $715. My next vehicle won't likely be a GM. I'm the second owner for this van..purchased it in 03 with 25000 miles on it from a nice older couple who drove it to florida 3 times a year. I cross my fingers as I have not had to have the intake gaskets replaced due to the dexcool coolant.
  • Technical question: What is an acceptable level of coolant system pressure loss when doing a pressure check? I hooked up a Stant pressure test device to the filler neck, pumped it up to specs in GM shop manual for Silo, left set for 2 minutes per manual. Gauge shows 1 psi pressure loss over 2 minutes.

    Is this acceptable? Had an analysis done for the oil and they found traces of coolant, may point to bad head gasket. Coolant loss is very minimal. I just added less than 1qt to expansion tank first weekend in April, added 1-2qts this past Christmas, nothing in between.

    Any interpretation of this information is appreciated.
  • Does not sound good. Probably a bad head gasket which is common on the 3.4 litre V6. The last time I visited the NHTSA web site, there was 247 Technical Service Bulletins (TSBs) for the Montana/Lumina/Silouette trio. Fix it soon or sell it will destroy your engine very quickly.
  • fknstrfknstr Posts: 3
    Can you give me a step by step on how to get to the bottem bolt on the thermostat housing? What all has to be taken off to get the upper intake manifold off?
  • I now know that the lower intake manifold gasket is leaking. My belief is that this is the problem. But is it a certainty that coolant and oil mix at the intake manifold gasket? I've seen this happen on a GM 2.8 V6 before.
  • I have not done this myself, but I will be doing it in a couple weeks. Factory shop manual says 1. remove air cleaner and duct assembly; 2. drain coolant to below thermostat level; 3. remove crossover exhaust pipe; ... then it goes into removal of the hose and housing removal. Doesn't look like anything else comes off according to the shop manual. For the upper intake manifold, 1. MAP sensor; 2. EGR valve; 3. vacuum harness assembly; 4. accelerator cable bracket and bracket bolts; 5. purge valve and throttle body. According to the shop manual, you are then ready to do the upper manifold bolts.

    Won't you please tell me how much fun you've had when you are done. :)
  • vicarsvicars Posts: 2
    We have a 2003 Venture. While taking a trip, we will stop for gas or food (running the van for apprx. 30 min or so). When trying to start again, the van will not start. Engine turns over and sounds good other that just starting. After letting the van cool down, it will start and run good.

    We have replace the cam and crankshaft sensors.

    Does anyone else have this problem???? :(
  • 442dude442dude Posts: 373
    Sure sounds like a bad crankshaft position sensor but you said you have replaced it...

    Can you hear the fuel pump when you 1st turn the key? Maybe a bad fuel pump relay?
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