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Automatic Transmission Won’t Shift Until 4000 RPM

Does improper cooling system cause transmission shifting problem? My 2000 VW Jetta VR6 automatic transmission won’t shift until an engine speed reaches around 4000 rpm. It first happened on the way to work. It is just around 10 miles away and usually takes less than 20 minutes. But on that day, there was a heavy traffic and took more than an hour to get to the work place. When I almost got there, I noticed a transmission wouldn’t shift from 1st to 2nd.  Because I had just bought the car and I didn’t know any repair history, I assumed that transmission fluid was the cause and time to change. I replaced the fluid with a new filter without thinking or checking any further. Contrary to expectation, the old fluid looked very clean and didn’t have much metal flakes.

Luckily, it didn’t happen on the way back home. But soon, it started happening again. It didn’t happen all the time, but it happened after driving in traffic for a long time, and especially on a hot weather. So I suspected a bad transmission cooler.

This makes sense of the occasional problem only when hot. This time, however, I checked a little more. I used an obd scan tool to see if a temp was really high so I could make sure that transmission cooler was bad. At a glance of obd data, I couldn’t help noticing that a coolant temperature was high. I checked this in the middle of winter, but it stayed between 204.8 and 217.4 degree Fahrenheit (96 and 103 degree Celsius), although temp gauge in the dash board pointed to 190. A cooling fan didn’t start until a temp got over 212 (at a low speed). According to ALLDATA, the fan is supposed to start at high speed when temp is between 210.2 (99) and 221 (105). The temp range of low speed is between 197.6 (92) and 206.6 (97).

I believed this had to be corrected first whether the transmission cooler was bad or not. I changed a thermostat, a fan switch, and a temp sensor, but it was the same. Then, I changed a fan control module and a water pump, but it was also the same. Temp stayed high, and the transmission wouldn’t shift until it reached over 4000 rpm.

Because a radiator looked absolutely new, I didn’t change one. Almost all component of cooling system was new now. If I jumped the terminal of a fan switch connector, it made the fan start at both low and high speed. When looking for the solution online, I found a low temp thermostat and fan switch.

DSCN3594

no triangle switch

low temp thermo switch 75-82

square only

DSCN3607

needed to convert

There are several thermostats that open at different temperature, and I chose 176 (The standard is probably 190). As for a fan switch, it was kind of hard to find. I don’t remember how, but I manage to find it here. I bought 167/180 (75/82), and the standard one is probably 203/216 (95/102). (In this store, they have much lower temp thermostat, 158, called Ultra Low Racing Thermostat and triangle-to-square connector harness, too)

After I changed them, coolant temp is between 195.8 (91) and 204.8 (96). Temp is still higher than it is supposed to be, but my car drives well now. The shifting problem hasn’t happened so far. The time I changed these is in March, but it is still cold weather here. I don’t know what is going to happen in summer. If it does, I may need to change transmission cooler or install aftermarket cooling fan and an adjustable controller.

These tools were very helpful!!!

bluetooth obd adapterKD Tools 41720

How to Replace Audi VW Rear Brake Pads w/electric parking brake

Some new Audi and Volkswagen vehicles need a special type of an electric device to change rear brake pads. Without this, you cannot push a piston back into the caliper. Those vehicles use electric motors and module to set or release the parking brake. After deactivating electric parking brake, you have to push the pistons back into calipers manually, then replace brake pads. After putting back the calipers, electric parking brake have to be reactivated. Since electric parking brake module is very sensitive to low battery voltage and the power is needed to operate an electric parking brake, you had better connect a charger to the battery during the job.

The software in this video is called VCDS (VAG-COM Diagnostic System). It is very useful diagnostic software for Audi and Volkswagen vehicles. It can access to all vehicle systems such as, Engine, ABS, Airbag, Radio, Climate Control, etc… The software needs a cable that connects vehicle control modules with Windows PC via OBD port. For more information about VCDS, click here.

The important thing is that you should know the whole procedure to change the rear brake of these vehicle. Since the system is still new technology, many people don’t know about this process. Maybe, most technicians or home mechanics try to push back the piston in a regular way. However, after a few attempts, they should stop doing and try to look for some information. It is always important to refer to the manuals or internet whenever you doubt or notice something unusual.

 

GM Fuel Pump Wiring Diagram

This is a story from my personal experience as an auto mechanic. I worked on 1996 Chevy Tahoe V8 5.7L. The owner of the car complained that the car was hard to start after he parked for a while. Once it started, it drove fine and never had problems such as the engine stalls and shakes. After the engine shuts off, it could start right back if the car did not sit for more than 5 minutes.

First, I suspected a fuel leak. 5 minutes are enough time to lose the pressure in the fuel system if there is a leak. I thought there was too small leak to affect the engine performance. I thoroughly checked by leaving the car on the lift for more than an hour, but I could not find any leak. I scratched this possible cause from the list.

My next target was a fuel pump: the pump delivers fuel and creates fuel pressure. I thought the fuel pump did not work hard and fast enough. I installed a fuel gauge and measure the fuel pressure, and that was it! The pump built up the pressure just before and after the engine started. When there was no pressure, the engine would not start. That forced me to think of a leak, but I had not found anything earlier, and I soon noticed that the pump was not working when experiencing the problem.

At that time, I found it a little odd. Because the symptom indicated a physical problem like a leak, but it is an electrical problem. I came up with some things, but none of them accounted for all the symptoms. Time was up. I told the customer to come back tomorrow, got off work. As far as I know, the customer never came back to the shop. The problem was not solved until I happened to see a wiring diagram of the same car.

That was a long time ago. I was a newbie as an auto mechanic, and the shop I worked for never had auto repair manuals or wiring diagrams. If I go back to the past and the same situation, I would go straight to the library and try to look for a repair manual instead of wait for more than 5 minutes every time I tried to locate the problem. There would have been enough time to fix the problem and give the car back to the customer on the same day.

Looking up wiring diagrams is a short cut for finding the cause of problems. Reading repair manuals before you start a job saves your time. This is one of my experiences that remind me how important auto repair manuals are.

In case you wonder what was the cause of the problem on Chevy Tahoe, look at the diagram.

1996 Chevy Tahoe GM Fuel Pump Wiring Diagram

A relay for fuel pump was bad whole time. On older GM vehicles, an engine oil pressure switch is giving power to a fuel pump while the engine is running. ECM sends a signal to the relay at the item of only start-up.

How To Do It Yourself Auto Repair

You should know how to fix your car before you start a job. Otherwise, you will waste your time by opening up some other parts that are not related with the problem or going to a parts store to buy extra parts and tools. Preparing for everything lets you save your time and fix your car easily. Let’s see more details how to do it yourself auto repair.

There are auto repair manuals because you can look up not only when you get lost in the middle of the job, but also before you start the job. You can get the outline of each job, tools you need for a repair, or you can tell how long it normally takes to finish a job so you choose the best time to do it without a rush.

Repair manuals tell you whether you need to use a jack and crawl under the car. This helps you decide where to repair your car. You do not want to do this kind of jobs on a dirty ground. Even if the ground is clean but dangerous to use a jack for some reasons such as it is not level, or there is no room to place a jack when you work in your tiny garage, you will have to change the work place. Imagine all procedures of the job you are going to do and you can pick the best place and position for the job.

As for tools, you should own a basic mechanic tool set for any kinds of job. Buying a set is much cheaper than buying items one by one. You should own a basic size range of sockets and wrenches, 1/4, 3/8, and 1/2 ratchets and extensions, pliers and screwdrivers, and so on. You will buy the other tools individually when you need them.

To do auto repair, you need not only tools ,but also some equipment sometimes. If a job is a water pump replacement or a radiator change, you do not forget about a container to catch anti-freeze: however, there are many repairs that require to disconnect coolant hoses and drain anti-freeze. Whether you work on a street or in your home garage, you should not mess up the ground.

As you see, looking up information in auto repair manuals in advance have many benefits. You can save your time, perform a job smoothly without hassles, and keep your work place clean so that you will contribute to protect the environment.

How To Get Free Repair Manual Online #2

There are many ways to get online repair manuals for free. Just typing your car’s make, model, year, and a specific term such as a name of parts, you will see many websites, forum posts, etc… Some websites are created by auto repair manual companies and they cost you a subscription fee to use their manuals. But forum sites is usually free. By typing your car_model+forum, you will find the forum and you may find the answer you are looking for as well. You may not find the information you need but you can also post your question and wait for an answer from other forum users. This may be a little time-consuming way to do. But it is free. Even if you have a good repair manual, you should keep in mind that there are always forums to help your auto repair jobs.

What else? Some auto parts store offer online car repair manuals for free. Autozone.com is popular for free manuals. You will need to register (also free) to get access to the manuals. AutoZone has manuals of many models and years and you will have access to all of them after a free registration. The manuals are neat and easy to see and navigate. The contents are somewhat lacking of information as compared with paid online repair manuals. But again, it is free and no harm to you except you keep receiving promotional emails from AutoZone.

As a useful technique, there is an Image search to take advantage of. Most browsers are default to Web search. By changing it to Image search, you will have greater chance to find wiring diagrams, or pictures and illustrations. Needless to say, visual contents are helpful in finding the location of the part, estimating the difficulty of the overall procedure. Using Image search sometimes save you a lot of time when you try to get free repair manual online.

Online car repair manuals keep our planet clean. They don’t consume trees. That is why many publishers such as Chilton’s and Haynes tend to have more and more online car repair manuals. To use most online car repair manuals, you need to pay a subscription fee, monthly, annually, or even lifetime, depending on publishers. If you have no clue to choose which publisher is the good, look for a sample page in their websites. Most publisher’s website have sample pages. ALLDATAdiy.com has complete manuals of 2 specific vehicles as a sample. If your car’s models and year are the same as these sample vehciles, you are so lucky to use the manuals for free.

How To Get Free Repair Manual Online #1

You probably know that auto repair manuals are very important when you work on vehicles. Before you start opening up the parts of your vehicles, it is wise to look up the procedure of the repair or possible causes of the problem in repair manuals. Repair manuals are great help to both do it yourself auto mechanics and professional auto mechanics. You can get exact information you need in no time by subscribing online car repair manuals. But what about a free repair manual online? You may have heard that you can get repair manuals for free. Or you see many phrases, such as free auto manuals download, car wiring diagram for free, etc…

It is true that there are many free repair manual online. One of places you can find free repair manuals is a library. You don’t have to go to the library right now. Because the library may not have the manual you are looking for. Libraries have their own websites. Visit the website first and type your car’s model and year. After you make sure they have the your car’s manual, go to the library and check out. But printed manuals don’t have as much information as online repair manuals have.

Because of the advance of technology, newer vehicles need more and more pages. Printed repair manuals of newer vehicles should be several times thicker than the manuals of older vehicles. The reason you don’t see such books is the contents of printed repair manuals are limited to basic information. They don’t have the information of new technology or detailed wiring diagrams. Of course, how much information you need depends on the level of your skills. If you do only routine maintenance like oil change and tune up, printed manuals are probably sufficient for you.

The drawback of printed manuals is that it’s hard to find pages you collect information from. Unlike online repair manuals, there is no search box to type names of parts you are going to replace or trouble code’s number you just retrieved by a scan tools and want to know the cause. After you manage to find the pages, make sure to copy the pages. Don’t take the manual to a work place and look it up while working. Soon it will be full of fingerprints on all pages. Remember they belong to the library.

Regardless of disadvantages, printed repair manuals are still around on the market. That is because they target on do it yourself mechanics who do only basic jobs. Again, they are enough for those who do only routine maintenance. If you want to own the manual instead of borrowing from library every time you need, you can find almost all cars’ manuals on the Internet. Haynes and Chilton are very reputable publisher of auto repair manuals for many years. You can also find used manuals as well as new ones with discount on eBay.