Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Toyota Sienna Maintenance and Repair (2003 earlier)



  • jeproxjeprox Posts: 466
    most new cars now have the a/c wired to your defroster for the windshield. when you turn the dial to defrost your windshield, it automatically turns on your a/c. some old american cars does this also.

    the cold air from the a/c helps clear up your foggy windshield much faster than hot air. i personally don't like this set-up coz when you set your dial to defrost, that means your a/c is on and you are burning extra gas! just imagine, you have your a/c on during the winter to clear up the foggy windshield!

    my used caravan was like this and i was wondering for the longest time why i use so much gas! coz i bought the van used, i didnt have a manual so i didnt know until a friend told me.
  • lsaclsac Posts: 22
    I have posted Dan's article at Try to get a clue for your van if you happen to notice the blink. According to owner's manual, AC comes on when dial is turned to defogger.
  • smfransmfran Posts: 432
    The A/C is necessary to defog the windshield not because cold air is better than warm air. It is because conditioned (dry) warm air absorbs moisture better. Damp unconditioned air will not defog the windshield; warm or cold. Even with the A/C on, cold air will not absorb the moisture.
  • deg856deg856 Posts: 120
    The power sliding door on the driver side of our 2001 XLE (21K mi., 18 months old) acted up yesterday again. When we attempted to open it, it would move a fraction of an inch and stop. Manually pulling the sliding door open past the half-way-open point activated the power mechanism, which reversed the door and closed it against our wish. We ended up deactivating the power and used the door manually all day. When the door was fully opened and the power was activated, it closed upon command without any problem, so the problem was limited to the opening cycle. This was new since we previously only experienced problems with closing, but not opening.

    The same thing occured two days ago and fixed itself. Since it occured again yesterday, I made a service appointment with the dealer for this morning. However, when we got home late last night and gave it one more try, the power door worked again. This morning I tried it a few more times and it worked just fine, so I decided not to go to the dealer - until next time.

    We've had intermittent problems with this power door for over a year - it stopped working a few times and each time the problem went away by itself in a day or two. A previous trip to the dealer did not unveil the cause of the problem. The cold and the rain appear to be a factor (this is just a casual and unscientific observation). To us the power door is such a cool feature, we sorely miss its utility each time it stopped working, even only for a short time.

    Aside from this intermittent problem with the driver side power door and an intermittent speaker (rear driver side; scratchy noise) problem, the van has been excellent.

    San Jose, CA
  • I have a 01 xle. deg856 you may want to check out my post 1939. I had similar problem(s) as you and others have listed. You may want to have the dealer check the door computer. Trust me, it did not "fix itself". It is an intermittent problem. Once the door computer was replaced the door has been working great. I have the part number listed on the other post.
  • kw6kw6 Posts: 26
    This happened to me about a month ago. I was in a heavy rainstorm with defrost on, and all of a sudden I felt extreme humidity (I live in Texas so I know what humidity is). I looked, and the light was blinking. I happened a couple more times. I took it to the dealer later that week, and the mechanic said that the belt was slipping because of all the rain. He said the belt was tight.
  • deepandeepan Posts: 342
    jeprox i do understand why the a/c is needed and have no issues about it. my question is on the sienna when you turn the front defroster on does the LED on the a/c button light up. I know the a/c turns itself on just am not sure whether the LED should be lit. Could you chk this please.
  • jeproxjeprox Posts: 466
    on my sienna, when i turn the dial to defrost - the a/c light does not come on. i read the manual and it didnt say anything abuot the a/c coming on when you turn the dial to defrost. i also checked under the hood to see if the compressor is running - didn't see it running. so my conclusion is that the a/c does not turn on when you switch to defrost.

    the air (with the a/c on) is much colder compared to the air coming out when you're on defrost. try it yourself and see if you get the same results.
  • deepandeepan Posts: 342
    This is interesting. the air being colder with the a/c on and warmer with just the defrost on could br because the temp gauge is turned to the warm side. the windows and windshield clear way quicker and i thought the /ac automatically turned on. All the new cars i've been in automatically turns itself on including my dad's 2000 camry. where exactly is the compressor located. I would like to chk it just to see it myself.
  • jeproxjeprox Posts: 466
    when i checked mine, the temp. is set at the coldest air (blue).

    pop your hood open and the compressor is on the front passenger side. it is to the right of the windshield fluid bottle and below the alternator. it's shaped almost like a can of paint with a belt pulley at the end. when the a/c is on, you will see the the compressor turn. there's a black round piece attached in front of the pulley. when your a/c is on, this piece will start and stop. it turns (on) when the set temp. rises (warm) and it turns (off) when it reaches the set temp. (cold).
    when the a/c is off, this piece does not move - only the belt pulley rotates.

    my sister's 1997 camry turns on the a/c automatically when you switch to defrost. the a/c light comes on as well.
  • deg856deg856 Posts: 120
    Thanks for referencing your previous post on this topic by message number. Our van is still well within the warranty period so we can afford to wait until the door acts up again. Next time we'll try to "preserve the evidence" so we don't have to listen to the dealer say, "But we can't make it not work..." like last time.

    San Jose, CA
  • PekesPekes Posts: 6
    My Sienna is a '99. The ac light goes on when in the defrost postition - plus I can see the tach change so I know the ac has kicked in.

    I like this setup because (a) it works very well, especially in this wet winter climate on Vancouver Island; (b) I believe the ac compressor is less likely to have problems since it's being run more often - not being used for a prolonged period could cause bearings to seize, IMHO.
  • When you select defrost, Toyotas (both my Tundra and my Sienna) activate the a/c. That's the way it's designed. The reason for this is that the a/c compressor forces moisture out of the air - then the dry air is passed over your heater coil and onto your windshield. It's a superbly efficient method for clearing fog from the windshield. It may also improve the durability of your a/c system (more on this).

    I have aways done this manually in previous vehicles I've owned - the owner's manuals tell you this, it's not an urban legend. Simply select defrost and hit your a/c button. Adjust temp accordingly.

    No, the LED (on both my 00 Toyotas) doesn't come on when you select defrost. And I don't think you can run defrost when you've got recirc selected (it defeats the purpose and only makes it the fog worse).

    As to the gas mileage problem - I sort of agree that I would prefer to manage the a/c compressor myself. But a mechanic told me once years ago that you need to run your a/c compressor periodically even in the winter or the system will tend to fail earlier - seals or belts or something. Since then I've always used a/c in conjunction with defrost in the winter and I haven't had problems with my a/c systems in all the cars I've had over the years.
  • jeproxjeprox Posts: 466
    thats strange that my a/c does not turn on when i select defrost. mine is a 1999 model also. i have the CE model and i assume you have the LE or XLE coz u have a tach.

    i wonder if you have one of those automatic climate control system.
  • cliffy1cliffy1 Posts: 3,581
    The AC light will not come on when you hit the defrost. That doesn't mean it isn't on. Toyota was getting a lot of complaints in the service department from customers who could not understand the benefit of having the AC on with the defrost. They thought there was a defect so Toyota removed the visual indicator. Complaints have reduced.
  • I have a 2002 Toyota Sienna XLE with third row bucket seats. Since the day We bought the vehicle there has been a rattle in the right rear seat. It sounds like the seat does not fit tight into the anchors on the floor and when you go over bumps you get this loud rattle. Have had it in to the dealer twice...first time they told me the head rests needed to be all the way down...they never even test drove with me to hear the noise. Second time they secured the cross bars on both seats and when I drove it with technician it was fine. By the time I got it home it was making the noise again.

    It is so annoying as it is loud...even the technician said it was annoying. Has anyone else encountered this problem? Any suggestions? Dealership said there was not much else they could do. My reply was they better find something to do as I paid close to 30 thousand for an annoying vehicle.

    Thanks in advance
  • A couple of things you can try to reduce the rattling. One would be to try using some electrical tape on the anchors on the floor. I would guess that the rattling is from an anchor on the seat locking with a bit of play in the seat itself, allowing the anchor to rattle. The other option would be to add some sort of padding under the anchor points so that it will still seat firmly, but will not have enough room to rattle. Hope this helps.
  • Run, don't walk and insist that the computer be replaced. I have been screwwing around since 11,000 miles, on both doors. The computer was replaced on the drivers side and it is now my passenger side power door. I am just over warranty and the dealer now wants ME to pay labor and he will pay parts. I am going in today to say NO WAY. Other than these doors Its been a great van. My car was brand new and I experienced these door problems.
  • Can anyone help me? I have a 1999 XLE which has a problem with both the heating and air conditioning system. The problem is that when I am idling or in very slow traffic, the heating and cooling systems stop working (fans keep blowing but a/c or heat stops coming out of the vents). As soon as the car starts moving at any reasonable speed (30 km plus) the system will start working again after a couple of minutes.

    I have taken it to the dealership twice to complain about the air conditioning system and both times they said nothing was wrong. You try sitting in a traffic jam when it is 100 degrees outside with two kids and no a/c. It is not a pretty sight!

    Now that it is winter, we have the same problem with the heating system. Once we are stopped in traffic, the fan starts blowing cold air. A few minutes after the car starts moving, the system starts blowing warm air again.

    Can anyone suggest what the problem might be?
  • rfp1ncrfp1nc Posts: 10
    As noted in a previous post, Toyota replaced the computer in our passenger side sliding door, $800 but fortunately under warranty. Now the driver's side door is having the same problem... won't close. 1,500 miles left on warranty and I'm bringing it in this week. I'm concerned that this convenience will eventually be a major recurring expense once it's out of warranty.
  • jeproxjeprox Posts: 466
    you have a strange problem.
    are you saying that when you stop, no air is coming out of your vents or there is air coming out but just that it's not cold enough or warm enough? you said your fan keeps blowing so your heat and a/c must be working.

    when you're stuck in traffic, the thermostat maintains your cold or hot temp. i find that the sienna a/c is not that cool during hot summer days.

    when you're using the a/c, make sure you set your air flow to recirculate - this helps a lot in keeping your interior cool.
  • jeprox,

    Let me try to be clearer with my explanation. I have two separate problems, one with the a/c, the other with the heat.

    The problem with the a/c is that when sitting idling (or in slow moving traffic) the cold air turns warm. The flow of air through the vents does not change. As long as the car remains stationary, the air remains warm. A couple of minutes after the car starts moving again, the air gets cool again.

    A local mechanic seems to think the problem may be with a fan inside the engine which blows on the coils when there is too much heat. He believes that it may not be working correctly.

    My other problem, with the heat system, seems to have been corrected. This problem appeared to be exactly the same issue as the a/c in that warm air turned to cold when sitting idle. We were advised that this problem was due to a low coolant level. Once the fluid level was topped up, the problem went away.
  • cliffy1cliffy1 Posts: 3,581
    Allow me to comment on the AC issue. Is this problem only with the rear AC or the front as well? The reason I ask is because the rear AC issue is well known, as is the reason for it. The ducts are in the roof. That means, when you are sitting still with the sun beating down on the roof, the air in the ducts can't remain cool. When you move, wind outside the car dissipates the heat on the roof, rather than the air in the ducts. Nothing can be done about it.
  • pjksrpjksr Posts: 111
    I had a similar A/C problem in my old Ford Aerostar. It was caused by bad refrigerant pressure sensor, causing the compressor to switch off inappropriately. You probably need diagnosis by someone really familiar with A/C systems.

    It is also normal, I believe, for A/C temp to rise a little bit at idle, then to get cooler after your RPMs go up.
  • You said you "topped off" the coolant. Is it time for a complete flush and fill? When my wife's 2000 was taking longer and longer to blow warm air when it was cold outside, I checked the book and I was overdue for flush and fill (I think it's every 20K). Check the book and see if you're due. This would affect both heating and cooling efficiency.
  • deepandeepan Posts: 342
    on our sienna there are two ducts(vents) under the font seats for the rear. When its blowing heated air i can feel that the passenger side vent blows considerably more than the driver's side. Was this design intent.
  • jasdmwjasdmw Posts: 118
    Did you check to see if the drivers side vent is fully open? There is an adjustment wheel on the top of the vent to restrict the flow of air from this and the passenger side vents. I usually have to close the drivers side down a bit to reduce the air flow as it's quite strong.
  • I'm planning to buy my sister-in-laws 1998 Sienna, purchased around August of 98 with about 65K miles. Oil has been changed regularly every 5k miles the first 20K. Thereafter, every 3K miles.

    I'm thinking of changing to synthetic oil. First, using Amsoil Engine flush, then going to Mobil 1, changing oil every 5K miles or 6 months, which ever comes first.

    After reading about the engine sludge issues, I'm worried about the sludge breaking loose and blocking those ports during the flush process.

    Does anyone have an opinion?

  • pjksrpjksr Posts: 111
    momo: How do you know you have any sludge? The only way to tell is to open it up (valve covers)... If the oil was changed as indicated, the engine should be fine.

    If I were to do a "flush," I'd probably just go with a high-detergent/dispersant oil, like a Delo or Delvac, which are tricky to find in multigrades...

    Running actual, true synthetic oil (PAO) like Mobil-1 is a good idea if you don't wish to change your oil within 3000 miles or less.

    You, of course, will also like to update things in the engine comparment like the air filter, pcv valve, hoses, ATF, coolant, themostat, fuel filter (on the fuel "rail"), etc.

    Come to think of it...why not just buy a 2003? There are some great deals going--and the headlamp assemblies are more cool!
  • Pete,

    It appears that I made an assumption (dangerous, I know) that with the regular "dino" oil, that there would be some build up of sludge on the gaskets in the engine, maybe drying up the gaskets which is another issue that I think may come up if I go to synthetic. With the engine flush, I was thinking that this would "remove" this build up from the gaskets, thereby blocking the oil ports. Also, do these engine flushes really work?

    Maybe I'm being paranoid.

    As for buying a new Sienna, the boss (wife) would rather go for the Odyssey if that was the case....

Sign In or Register to comment.