Subaru CVT Fluid Temp checks

[Raven]

Hey guys,

I have a Bluetooth to OBDII adapter to use with OBD Fusion on my iPhone. I need to check CVT trans temps on 2014+ Subaru TR580/TR690 transmissions. For research I poked around the internet and dug out data from the ScanGauge category for transmission. Example:

Code


NAME TXD RXF RXD MTH NAME NOTE

CVT Fluid Temperature (°F) 07E1221017 C46205103617 3008 00090005FFC6 TFT 4.22+ Required"


This is translated to Torque/OBD Fusion codes like so:

Module/Header: 7E1
OBD Mode: 22 (If Torque, then it's 221017)
PID Number: 1017
Equation: (((A*9)/5)-58)

I tried it in a car today, not no response back. The reason I would like to make this post is to figure out why, because the CVTs on the Subies are really picky, and a lot of us are doing CVT flushes on them. If the fluid is not in the correct temp range (95-113 deg F, 35 - 45 deg C) then it is Not Okay and the easiest way for the common folk like us is to use one of these wireless bridges and a program on our phones.

Can someone else who has one of these setups (Torque/whatever) and a Subie w/CVT check my work?

 

[benjy]

using Vag-Com on a VW on a 80 ish degree day showed the correct temp for a fluid drain + fill. not a CVT which i would never touch but a 6 spd tiptronic tranny used in various cars, so guessing your temps on a similar day after driving would be fine + good luck with the CVT as i wish for my sisters doggy 18 impreza!

 

[SubieRubyRoo]

Why did you subtract 58 in the equation? Normal conversion from C to F is A*9/5+32, and you shouldn't need the parentheses around A & 9 because order of operations takes precedence, and will still give you the same result.

 

[JTK]

A flush as in a cooler line exchange with a dual reservoir machine?

I've owned a few late model Subarus with CVTs and followed Subarus in general for years. I wouldn't say their CVTs are more picky, problematic or complicated to do a fluid service on than any present day automatic transmission.

I'd personally do cold drain and fills with it like I do my Nissan CVT. Measure what you took out, add that same volume back in.

If temperature is still a concern, I'd just have the vehicle up to normal ops temp or shoot the pan with an IR gun to see if you're in range. But that's just my unsanctioned, unprofessional opinion.

 

[ARB1977]

At least on the Honda CVT measure what came out then run through the gears, remove check bolt to get a trickle of fluid coming out.

 

[JTK]

Originally Posted by ARB1977
At least on the Honda CVT measure what came out then run through the gears, remove check bolt to get a trickle of fluid coming out.


I hear ya, but Honda doesn't spec a temp at which to do this?

My Nissan has a drain plug, a top refill tube and a level check plug, but Nissan still recommends checking for the 'dribble' at a specific temp range. I'd have to look it up for Nissan Jatco CVTs, but it's something odd like 95-122F. Warm, but not super hot. Obviously the level has to be checked with the engine idling and the transmission must be in park. If you pull the level check with the engine off, CVT fluid will gush from the plug.

 

[Raven]

Originally Posted by SubieRubyRoo
Why did you subtract 58 in the equation? Normal conversion from C to F is A*9/5+32, and you shouldn't need the parentheses around A & 9 because order of operations takes precedence, and will still give you the same result.


The reason is ... I don't know. The math comes from the Internet: the last four characters are signed word characters in hex form. FFC6 translates to -58.

Anybody else have a Subie with the CVT and a Bluetooth adapter widget?

 

[Raven]

Bump for more exposure.

 

[2dogs]

If you have access to an android phone you may be able to use the Torque app with the Active OBD add on. On my '16 Forester CVT temp is displayed.

I like JTK's idea of just doing it cold making sure to measure properly. Only negative with that is if the CVT was low on fluid for some reason, it would still be low after your drain & fill.