Question about 2004 Buick Rendezvous
I have a 2004 buick rendezvous fwd. the service vehicle soon light comes on and is showing no codes when scanned by the gm diagnostic computers. My friend who is a GM Master Tech hooked the code reader to it and extracted all of the history and no codes at all were showing. He then deleted and updated the software that runs the computer the car runs better bt the light still comes on.
History of minor problems:
after updatign the software we were sitting in the car and noticed the cd player electric motor was running constantly as if a cd was stuck in it but after investigating I found 26 cents in it. I removed the change and turned the car on and the light went off for the first time and the cd and radio LEDs were bright for the first time as well so I put the car in gear and the service light came back on as soon as i put it in gear and then the LEDs on the CD display went dark again. I have noticed the engine is running hotter than normal bt the temp is in the 100's here as well i think it might have a thermostat issue and possibly not related because it is not a service engine light but service vehicle light. I drove the car yesterday on a long drive and while driving the interior A/C fan switch that has 4 positions for the climate control had the third position fail. about that same time the A/C stopped blowing cold and actually started blowing hot air I checked the temp guage and it was between 1/2 and 3/4's which is a little hotter than normal but the outside temp was at 105 F. I killed the car for a few minutes and then restarted with the fan set to the lowest position and the radio off and then the engine temp lowered and the air started getting cold from the A/C again. at this point i started thinking about the cooling fan on the engine rather then thermostat??? also last summer the vehicle was running a little hotter than normal as well and the cruse control had quit working completly during this same time.. after chasing it for weeks, just by chance I happend to change the interior A/C filter in the glove box and when I did that the cruise control started working. So it told me that for some reason the vehicles power output from the alternator must be just marginally ok for these cars becuase as soon as the ac had to work a little bit harder because of the clogged filter it would not allow the cruise control to work while the system was under the current load. It is confusing. I am not sure how or if any of this is related but it has been out smarting the GM diagnostic computers. I want to disclose all the information possible so you have some history on the car. ANY ADVICE IS APPRECIATED
Check the water pump in
the car If its loose or blocked this can be the one reason for car to
overheat.And other thing to get checked is coolant leak.I agree with you that
coolant is full.But if its leaking then car will overheat.There is a test to
check the coolant leak.Its called coolant pressure test.You can get
it tested at any local car garage.Check to see if your automatic clutch is
working on your cooling fan on front of radiator.You can watch for operation of
fan while radiator heats up water for heater operation.If clutch is not working
It has to be replaced.Defective
fan clutches are a common and often overlooked cause of engine overheating. The
shear characteristics of the clutch fluid gradually deteriorates over time,
with an average loss in drive efficiency of about 200 rpm per year. Eventually
slippage reaches the point where effective cooling is no longer possible and
overheating results. (On average, the life of a fan clutch is about the same as
a water pump. If one needs to be replaced, the other usually does too.)
If the fan clutch shows signs of fluid leakage (oily streaks radiating outward from the hub of the clutch), spins freely with little or no resistance when the engine is off, or wobbles when the fan is pushed in or out, it needs to be replaced.
But if everything check out ok.Then check out if your car is really getting overheated or its just showing on your temperature gauge.
In many cases it has seen that car is actually fine and cold but temperature gauge shows its overheating.
Your engine may not be overheating at all. Your temperature gauge or warning lamp may be coming on because of a faulty coolant sensor. Sometimes this can be caused by a low coolant level or air trapped under the sensor.
Leaky Head Gasket -- Bad news because repairs are expensive. A leaky head gasket can allow coolant to seep into the engine's cylinders or crankcase. Symptoms include a loss of coolant with no visible external leaks, and white steam in the exhaust, especially after restarting the engine when it has sit for awhile. A leaky head gasket can be diagnosed by pressure testing the cooling system, or by using a "block checker" that pulls air from the cooling system into a cylinder that contains a special blue colored leak detection liquid. If there are any combustion gases in the coolant, the color of the liquid inside the detector will change from blue to green. A leaky head gasket can often be temporarily sealed by adding a sealer product to the cooling system. But for bad leaks or ones that cannot be stopped with sealer, the head gasket has to be replaced.
Also get the ignition switch and its connection checked.
Also check the steering wheel.and control stalk on the steering wheel.
Posted on Aug 02, 2010
Hi! This is definitely a PCM (powertrain control module) failure. The PCM has connectivity on all electrical current that runs inside the car including the engine and transmission. If the PCM is faulty it gives current irregularities just like what you're in now. Have the PCM replaced and you'll be good. The PCM is the car's brain thats why its very important. Hope this helps and have a good one!
Posted on Aug 04, 2010
The problem is the body ground module and GM is well aware of this problem,Have your GM friend replace it and your problems will be over.
Posted on Aug 02, 2010
I think that if the computer's service engine soon light goes on but there are no hard codes stored, then the computer is suspect. That's just my opinion on it.
The same goes for having no service engine soon light at all when you switch it to ignition on but haven't started it yet.
Posted on Aug 02, 2010
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Posted on Jan 02, 2017
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