Having trouble locating the VSS

[Ms3boosted]

Hey guys I have a 2012 mazdaspeed3. I recently started having problems such as my speedometer stopped working and my rpm won’t go past 3200 it’s like launch control kicks in. I have done some research and made a few calls and it seems to be my vss. But I have spent hours under my car and under my hood trying to locate it. I have also been told that it may be a abs sensor so I changed the front driver side as I was told that if one of the front work my problem should be solved. Any help or ideas would be greatly appreciated thank you.

 

[edmaz]

The VSS is almost completely hidden away behind a plate, which needs to be removed first in order to get at that sensor. Although your situation might be different, most transmission issues on this model will be caused by the TCM being cooked by the heat from the tranny. Never a bad idea to run through the sensor testing protocol first however.

 

[Ms3boosted]

Thank you for the input. I had no idea about the tcm being cooked. I take it finding the sensor test online should be easy? I’ve never done one before.

 

[Ms3boosted]

The VSS is almost completely hidden away behind a plate, which needs to be removed first in order to get at that sensor. Although your situation might be different, most transmission issues on this model will be caused by the TCM being cooked by the heat from the tranny. Never a bad idea to run through the sensor testing protocol first however.

When you say tucked away do you know where exactly it is tucked away? Cause I have looked everywhere and I had no luck.

 

[edmaz]

I found it on my 3i from underneath, orientated with feet facing toward the front of the vehicle. It's on the backside of the tranny case, covered with a small protector plate held on by 2 bolts. Everything with the tranny of your speed should be identical to the 3i.

In order to do the electrical testing with a multimeter, you would need to remove the connector to that sensor, and the TCM connector as well.

What code(s) were set?

 

[Ms3boosted]

I found it on my 3i from underneath, orientated with feet facing toward the front of the vehicle. It's on the backside of the tranny case, covered with a small protector plate held on by 2 bolts. Everything with the tranny of your speed should be identical to the 3i.

In order to do the electrical testing with a multimeter, you would need to remove the connector to that sensor, and the TCM connector as well.

What code(s) were set?

I wasn’t throwing any codes. Just one morning everything happened Speedo stopped working and the rpm wouldn’t go higher than 3200 and launch control started kicking in.

 

[edmaz]

I missed what you wrote about the spedo in your OP, and after rereading everything, I now see no reason to believe your vehicle has a tranny issue. It would be very unusual to have an electrical (TCM, sensor, solenoid,) transmission issue without having at least one code set. However, it's not an uncommon thing for there to be a crank sensor signal issue where there are no codes.

The first thing I would do if it were mine would be to test the crank sensor wiring. Although a scope is required to test the signal waveform, you can check the ground and reference with a multimeter, and also check to see that there is at least some signal being produced.

 

[Ms3boosted]

I missed what you wrote about the spedo in your OP, and after rereading everything, I now see no reason to believe your vehicle has a tranny issue. It would be very unusual to have an electrical (TCM, sensor, solenoid,) transmission issue without having at least one code set. However, it's not an uncommon thing for there to be a crank sensor signal issue where there are no codes.

The first thing I would do if it were mine would be to test the crank sensor wiring. Although a scope is required to test the signal waveform, you can check the ground and reference with a multimeter, and also check to see that there is at least some signal being produced.

I missed what you wrote about the spedo in your OP, and after rereading everything, I now see no reason to believe your vehicle has a tranny issue. It would be very unusual to have an electrical (TCM, sensor, solenoid,) transmission issue without having at least one code set. However, it's not an uncommon thing for there to be a crank sensor signal issue where there are no codes.

The first thing I would do if it were mine would be to test the crank sensor wiring. Although a scope is required to test the signal waveform, you can check the ground and reference with a multimeter, and also check to see that there is at least some signal being produced.

This is my first time having a problem like this. Where would this sensor be located and how exactly would I test it? Sorry for asking a lot of questions just these 3 weeks have been pita and I’m frustrated.

 

[edmaz]

That sensor is located on the front of the block near the knock sensor. However, I have to tell you that this one goes beyond simple and easy DIY. As I wrote above, an oscilloscope is required to read the sensor signal, and that's beyond what most DIYers have and can do on their own. So the only other choice is just fire the parts cannon and replace it.

But to make matters worse, a somewhat complex procedure is specified in the FSM for replacing the crank sensor, and it states that a special service tool is required as a part if the install of the new sensor. Don't know if the crank sensor can be installed by omitting that procedure, but I wouldn't want to remove the old one without knowing the answer for certain.

Sorry to say, but this is one of those rare cases where I'd advise against trying to DIY.

 

[Ms3boosted]

That sensor is located on the front of the block near the knock sensor. However, I have to tell you that this one goes beyond simple and easy DIY. As I wrote above, an oscilloscope is required to read the sensor signal, and that's beyond what most DIYers have and can do on their own. So the only other choice is just fire the parts cannon and replace it.

But to make matters worse, a somewhat complex procedure is specified in the FSM for replacing the crank sensor, and it states that a special service tool is required as a part if the install of the new sensor. Don't know if the crank sensor can be installed by omitting that procedure, but I wouldn't want to remove the old one without knowing the answer for certain.

Sorry to say, but this is one of those rare cases where I'd advise against trying to DIY.

Alright bud well thank you for all your help and your input I greatly appreciate it. I’ll see if I can borrow my mechanics scanner and see if it will pin point a problem or at least point me in a better direction than what my knowledge has lol