2001 V70 T5 - Slipping AW55 Solutions?

[Noie]

I appreciate the quick reply. The rainstorms just hit here in Western Washington, so it may be a few days before I get to replacing the sensor, but I will keep you posted on here as to how it goes.

One thing to note: I purchased the transmission speed sensor (sensor only) from IPD, rather than the sensor + wire lead from FCP. I suppose if it continues to throw the error then the issue lies in the wiring rather than the sensor itself.

Thank you, and thank you brother for his expertise.

~ Noah

[jlenny]

Good to hear! You may have to wire in the sensor, but it sounds like you already know that.

[dikidera]

Btw, a non-working sensor could absolutely cause slipping etc. The speed sensor is important for the calculation of inertia(there is a fallback to a working speed source e.g abs). And inertia is directly proportional to the pressure applied, since inertia is used for pretty much all pressure maps involved.

And depending on which sensor specifically this is, it is also used for turbine slippage aka torque multiplication, clutch slippage feedback etc, rate of change of input shaft which is crucial for not just pressure but how long to hold it aka important for timing of clutch apply, hold time, release time etc.

This is from my reverse engineering of the TCM so I am quite confident in this information. But of course the slippage could've been there beforehand so not saying this is 100% the reason, merely a possible reason.

[Noie]

Hi JLenny,

I braved the rain and pulled the output sensor off last night. It turns out the one I bought from IPD (volvo OEM) is slightly different than the one in the car. The one I bought from IPD has a female plug end where the lead wire should connect to the sensor. The one I pulled from the car has the lead hard-wired into the sensor.

I see sensors for sale online from FCP come with the wiring lead connected. However, unlike sensor in the picture you attached (where the lead plug connects into the car close by), the wire from my sensor runs up near the headlight (probably over 1 foot of wire is attached to the sensor to get it there). (I believe the one you pictured is a 2000 V70). FCP sells the wiring harness, but it looks like I would need to replace the input sensor as well to make the harness work.

Any advice you or your brother has on this? Images of the original speed sensor, original speed sensor wiring, and the new sensor that I do not think will work attached below.


Original sensor pulled from transmission. Wiring directly hard-wired into the top of it.

New OEM sensor from IPD, with female plug on top of it. (I have nothing to plug into it)

Notice how the wire/lead from the sensor runs directly forward. (the one you pictured plugs in nearby)

Here the wire from the output sensor, can be seen (just barely) running by the input speed sensor to the front of the car.

This is where I've traced both the output and input speed sensor wiring to. In between the airbox and the bumper.

Thanks, Noah

P.S. I did clean off original sensor and reinstalled, vehicle runs acceptably but error codes persist.

[Noie]

I am picking up more knowledge on the fly here as I sleuth around. But it appears I will need the entire harness, plus the two sensors so they interface correctly.

FCP claims this will not fit my vehicle, but I'm looking at this one: https://www.fcpeuro.com/products/volvo- ... escription


Here is the end of where my transmission speed sensor leads interface, front of the airbox. 4 pins, 4 wires (2 from each sensor).

I did get a can of air and blow all the dust off of it after I took the picture

[jlenny]

I noticed that the blue sensors like in one of your photos above are for the 05-07 cars. While I was looking at junkyard cars. The 03-04 XC70/V70/S60 seem to use the same sensors as a 2001, but they're wired different. I believe my brother took a sensor from one of those years (03-04) and spliced it into the existing harness on my 2001.

[Noie]

Alright, I went to the local junkyard and grabbed the complete assembly (both sensors & wire lead). I'll install later this week and post results here. I'm still debating, but likely will replace complete assembly instead of splicing. If a sensor is bad off of the junkyard part then I'll splice as needed.

I did notice the output sensor wet with transmission fluid when I pulled it off the junkyard v70. When I pulled mine from my T5 it was dry. I made sure to properly check my transmission fluid level on my car after I drain/filled it, but this has me second guessing my fluid level. I have also noticed I'm more prone to gear slippage during acceleration if in a sharp, high centrifugal force, turn. Maybe fluid is low and pulled to one side?

~ Noah

[abscate]

Here’s the 2005 wiring of the 4 pin speed sensor , maybe research what those designations are for help in rewiring?

[Noie]

Alright JLenny,

I successfully installed the sensors that I pulled from the junkyard. (I had pulled the entire lead including both the input and output sensor and plug-in).

Once installed, I tested it a little bit by driving city streets, and then stopped to clear the codes using VIDA. After clearing the codes, I turned the ignition off, then on to 1500 RPM, then off again , and then on again (like VIDA recommends). After that, the car, at idle, was building RPM into the 1000s with no throttle application. However, this uncontrolled RPM build was short lived, and settled back down to normal idle.

I did not reset the transmission adaptation, as I did this already when I changed the ATF fluid earlier this summer, and did not see a reason to do so following the speed sensor change. If you think there is a reason, or if there is another thing I should reset, please let me know.

After that I took it on the back roads! I hope your car is running as well as mine, because man! It has substantially increased acceleration consistency. No slipping during acceleration, or clunking when accelerating out of coasting. Smooth, smooth, smooth! No more worrying if I can get up to speed hopping on freeway. I felt like I was walking on eggshells every time I drove it before.



Interesting side note: I cleaned off all sensors after pulling them from junkyard. I inserted this one in the speed sensor hole, and took it out right after. It picked up all of this debris. I assume there are fine metal shavings loose in the transmission, and the speed sensor has a magnet inside. Does your brother think this is normal?

I'll report back here if anything develops or goes wrong. Thanks again for you and your brother's guidance!

~ Noah

[Noie]

Here’s the 2005 wiring of the 4 pin speed sensor , maybe research what those designations are for help in rewiring?

Thanks Abscate,

I was able to pull the entire lead with both sensors from a junked car, and since both sensors worked no splicing/crimping was required. Simple plug and play. (The wire leading to the input sensor was a different length/color than the longer one leading to the output sensor).