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What can cause a high cooling fan speed error in a 2002 Trailblazer?


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2015-07-17 17:45:20
2015-07-17 17:45:20
: Either a PCM reprogram or the fan clutch asembly will fic this condition. Replacement of the fan clutch is very labor intensive, and it is easy to put a hole iin the radiator or break something else if you do not have experience doing this procedure. TechJK------------------------------------

These errors are caused by software problems in the PCM. General Motors warrants this defect for unlimited mileage. Take your vehicle to a dealer for a free PCM upgrade to correct this and NUMEROUS other concerns (stalling, high idle, high fan speed, shift problems)

This is garbage- GM will tell you get real- totally rubbish. The problem lies in their monopolized parts (Dealer stock item only) Common problem - expensive part (entire fan assembly) and labor- (entire front end disassembly) I paid appx. $600.00 for this error code to be cleared. Good luck!


This two answers helped me a great deal. I had the exact same problem on my 2003 Trailblazer. The check engine light came on, I took my vehicle to autozone and they told me the code was P0495 (cooling fan speed high)but they did't know how to fix the problem. After loking at this two previous answers, I called the dealer and they told me that it would cost me $89.00 to reprogram my PCM. I took my vehicle to the dealer and before checking my vehicle, the mechanic noticed the noise my vehicle was making (like a jet engine) and told me that in addition to reprograming the PCM I needed to replaced the fan clutch. The total cost was going to be $747.00. I didn't have the money so I went home and looked on eBay. I purchase a brand new fan clutch for $130.00. I am not a mechanic and it took me about two hours to replaced the fan clutch. You need a 12" crescent tool to remove the fan clutch from the water pump pulley. After replacing the fan clutch, I was on my way to the dealer to reprogram the PCM but noticed that the vehicle was working great so I skip the dealer and went to the 7 eleven and got me a six pack to celebrate. My vehicle is working like new. I hope this could help somebody out there. Good luck

I have the EXACT same problem. My local Chevy dealer wants to charge me $800 to repair! I looked at the fan clutches on eBay (ZBRA) for $130. I noticed they have an electical connection but I couldn't quite see one on my clutch fan. Am I just not seeing the connection or is it possible that I don't have one. If I don't have a connection, is there a place to plug-in the new one? ALL 2002+ TRAILBLAZER/ENVOY/BRAVADA/SAAB 97X ETC HAVE A FAN CLUTCH ON THE I6 ATLAS ENGINE AND THERE IS ALWAYS AN ELECTRICAL CONECTOR TO IT. LOOK FOR A DANGLING WIRE THAT MAY JUST CONNECT TO A PLUG ON THE SHROUD.


Related Questions

if fan make a loud noise your fan clutch is bad

P1484 - Cooling Fan System Performance Cooling fan rpm error. When I had that code it was accompanied by p0495 .. Which is cooling fan speed too high ... I changed the fan clutch because they are notarious for problems .. And then 3 days later changed the water pump .. Cost me about 250$ to do it myself ... The shop was gonna charge almost 1800$ haven't had a problem since!

The 2003 Trailblazer speed sensor is mounted on the transmission. It is on the passenger side of the output end.

Trailblazer doesn't have a cable. There is a speed sensor on the Transmission. The guage is electronic and is the most common problem in the Trailblazer.

its on the tailshaft of the transmission

108 is how fast my 2003 trailblazer goes 108 is the top speed of mine as well but it also depends on the engine you have. I have the 4.2 lt.

Your speed sensor is faulty replace it...

The speed limit in any of the states!

Well, moving at speed will cause a cooling airflow around you, so sure.

The rate of cooling is the speed at which magma or lava crystallizes. When the speed is slow it results in big crystals. When the speed is fast it results in small crystals.

There is a vehicle speed sensor (VSS) and 4 ABS wheel speed sensors, one at each wheel.

Please be more definitive and let our technical people give you a hand with this at our forum. Is it the speedometer you are having problems with or a wheel speed sensor? Do you have a specific trouble code you can tell us? Trailblazer enthusiasts forum

The cooling speed. The slower the cooling, the larger the crystal size.

You have to replace the cluster. Then the dealer must reprogram it with the appropriate mileage. You can find vendors on EBay. Trailblazer enthusiasts forum

Velocity error,stylus speed error, pythagoras error,multiple echoes, zero line adjustment error

The speedometer doesn't work. It doesn't respond to the speed we are going.

Will a 2003 Chevy trailblazer transmission fit in a Silverado

Trouble code P0480 means: Low Speed (No. 1) Fan Relay Control Circuit

How do you know it is surging? The most common cause for a jump in idle speed while the AC is running is when the cooling fan cycles on and puts a draw on the alternator.

You have a 2 speed fan. If it is running on high then your cooling system is hotter than it should be.

well then go get it replaced

Not really. Speed is not the only factor of road accidents, most of the time it is HUMAN ERROR. According to research, 80% of all fatal injury on Irish roads are due to driver error. As a matter of fact "speeding" is also part of a driver error. Other errors are: Reckless driving, drunk driving, unsafe lane change, etc.

The front sensors must detect a full frontal crash. If it is a bit off center angle there is a possibility that they may not deploy as the energy required to cause deployment is dissipated .

Some motors are specially designed for low speed. Some are "invertor Duty" classified so that they can be run on invertor (VFD) normally with a high heat dissipating design. On low speed the cooling effect reduces drastically since the cooling fan is mounted on the same motor shaft. Hence a separate small cooling fan is mounted on the motor, driven by separate power such that it keeps running at normal speed irrespective of main motor speed, thus providing the required cooling effect.

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