Japanese CVT no-move conditions: Failsafe or defective TCM? - Transmission Digest

Japanese CVT no-move conditions: Failsafe or defective TCM?

The Japanese Automatic Transmission Company produces a continuously variable transmission (CVT) known as the JF016/17E, which has been fitted behind 2.0L to 3.5L engines worldwide. Here in the United States, there is a light version called the CVT-8LT for 4 cylinder applications (JF016E) and a heavier version called the CVT-8HT for V-6 applications (JF017E). Nissan refers to these transmissions as the RE0F10D (Transmission Code 3VX0A) and the RE0F10E (Transmission Code 3WX0A). Mitsubishi uses the F1CJC designations for FWD applications and the W1JCJ for AWD applications (Figure 1).

Shift-Pointers-September-Figure-1-1400
Figure 1.

One of the failsafe features that occurs when certain malfunctions take place is no throttle response, rendering the vehicle inoperative. We see this frequently with Nissan applications when such things are not right with the brake circuit or wheel speed signals. A slipping detection may also initiate a no-throttle response.

It is also possible to encounter a no-move condition which may be interpreted as a failsafe condition. Figure 2 provides a view of the valve body showing the solenoids it utilizes to operate this CVT.

Shift-Pointers-September-Figure-2-1400
Figure 2.

Figure 3 provides a complete hydraulic view of this type of transmission. If you look at the pressure supply to the manual valve, you can trace it back to the Select Solenoid.

Shift-Pointers-September-Figure-3-1400
Figure 3.

With a further look at the Reverse and Drive Circuit from the Manual Valve, you will notice that there are two check-balls in each of these circuits going to their respective clutch. Figure 4 shows where these check-balls are in the valve body. The reason for the double check-ball is to control both the apply and the release of the circuit.    

Shift-Pointers-September-Figure-4-1400
Figure 4.

As you can see, JATCO went to great lengths in controlling the apply and release of the clutches to prevent harsh engagements which in turn may damage the pulley assembly. In fact, the early design of the CVT 2, otherwise known as the JF011E CVT, utilizes two solenoids in conjunction with two valves along with the double check-ball configuration per circuit to accomplish this task. The drawback with this design is that garage shifts into gear can take up to two to three seconds and are to be considered normal.

With the Select Solenoid controlling supply pressure to the manual valve, it has the ability to control garage shifts into gear. The TCM receives input from the throttle positions sensor, the brake sensor and the range sensor when the selector lever is moved into reverse or drive. It then monitors the time it takes for the input speed sensor to ramp down to 0 RPM. The computer can adjust the apply time of the applying clutch through the Select Solenoid (See figures 5 and 6).

Shift-Pointers-September-Figure-5-1400
Figure 5.
Shift-Pointers-September-Figure-6-1400
Figure 6.

Nissan describes this process as follows: Based on accelerator pedal angle, engine speed, primary pulley speed, and the input speed, the optimum operating pressure is set to reduce impact of a selector lever operation while shifting from “N” (“P”) to “D” (“R”) Position. If it sees 0.3 to 0.4 seconds of engagement, a code P2813 will set with Nissan vehicles, typically for a mechanical failure of the solenoid. P2814 seems to set if there is an electrical problem while P2815 has been known to set for both a mechanical and/or electrical failure.

Depending on the way this solenoid fails mechanically, it could prevent all engagements, or allow for very harsh engagements. When the solenoid fails for harsh engagement, it could be due to a mechanically failed solenoid—but it could also be for another reason.

Read more columns from our Shift Pointers series here.

In one example of this, ATSG recently encountered on its technical help line a 2016 Mitsubishi RVR vehicle in Canada that exhibited a very harsh garage shift into gear. A DTC P2719 was set for “Abnormality in Select Pressure Solenoid Valve Function.” This is a performance code. If there were electrical issues, a code P2720 would set for low input, while 2721 would set for high input.

When reviewing data from a recorded movie, the tech observed that when this code 2719 set, PSI amperage dropped to 0 indicating max line pressure. The tech found this odd as the TCM noticed harsh engagements setting this code. Failsafe would be to adjust pressures to safeguard against damage and prevent throttle response. Throttle response was still functional and with PSI amperage going to 0, max pressure was present. This didn’t seem to fit the failsafe method of these CVTs.

The diagnostic routine for this code provided only two possible causes: the valve body assembly with solenoids, or a defective CVT. Since these options didn’t seem likely, further checks were made which included scoping solenoid signals. By doing this, it proved that a defective TCM was the cause, making sense of all these observations.

You May Also Like

10L80 and 10R80 pump gear differences

You may have seen an article in the August 2023 issue of Transmission Digest called “GM 10L80: A new kind of pump noise,” which goes over how the front cover housing in the 10L80 is fitted with a converter drive gear and idler gear. The idler gear drives the pump’s driven gear, and is press

You may have seen an article in the August 2023 issue of Transmission Digest called “GM 10L80: A new kind of pump noise,” which goes over how the front cover housing in the 10L80 is fitted with a converter drive gear and idler gear. The idler gear drives the pump’s driven gear, and is press fitted to this housing by way of a ball bearing (see Figure 1). It is this bearing that goes bad, making the aforementioned new kind of pump noise. 

Shift Pointers: What to do when the 62TE TRS tab breaks

How frustrating it is when on a hot summer day, as you go to open a nice cold can of your drink of choice, and the tab breaks off? You are outside, away from any tools to remedy the problem quickly. It now requires a MacGyver mentality looking around at the resources available to get

Going the extra mile: Proving your transmission repair suspicions

A 2003 Honda Pilot with a five-speed three-shaft transmission came into our shop with a customer concern that the vehicle had no power, and the “D” light was flashing. I first did a scan for codes to see what it came up with, and the scan tool returned four DTCs: P1298 (ELD voltage high), P0135 (H02S

RRfeature-1400
Diagnosing Ford 10R60, 10R80 and 10R140 series speed sensor issues

Ford 10-speed 10R series transmissions utilize four two-wire, Hall-effect sensors — TSS, ISSA2, ISSAB and OSS — for providing speed signals to PCM or TCM. They are supplied nine volts by a PCM or TCM and assist in the control of clutch apply/release timing that is used in determining shift quality, including TCC. Related Articles

Jatco JF613E transmission quick reference material

For those working on the Jatco JR613E transmission, a widespread transmission with plenty of applications, the following should be a helpful guide. Related Articles – Outgrowing the walls: The story of EVT Transmission Parts – Spotting different 68RFE designs through the years to avoid issues – Valve body and component suppliers: A comprehensive list Domestic

Other Posts

ATSG shop management training seminar coming soon

ATSG announced that it will soon be holding a series of management training classes for shops, beginning at the end of January. Related Articles – Are you down with CVT? – Shop Boss adds new user interface to its shop management software – How seriously should shops take the EV wave? Jonathan Sherman’s Management Training

ATSG-Sherman-1400
Shift Pointers: Failures caused by incorrect tire sizes

For years ATSG has produced a wide range of issues related to improper tire sizes on vehicles. Even under-inflated tires have been known to cause issues. Problems such as premature failure with an active 4WD transfer case will occur with incorrect tire sizes. Related Articles – Understanding lube flow control valves in Toyota/Lexus UA/UB80 transmissions

Shift-Pointers-Jan-Figure-1-1400
Transtar launches Transmaxx brand of remanufactured transmission products with ETE Reman

Transtar Industries announced that it is launching a new line of remanufactured transmission products, the Transmaxx line. Related Articles – Force Control Industries releases transmission fluid for oil shear clutch and brake applications  – TransGo introduces 62TE high pressure kit for vans – OTC releases TJHP15 transmission jack  To begin the Transmaxx line, Transtar partnered

Transtar-Logo
Understanding lube flow control valves in Toyota/Lexus UA/UB80 transmissions

The Toyota/Lexus UA80 and UB80 transmissions first came out in 2017 in Highlanders and Siennas. The UA80 is used in V6 applications, and the UB80 is paired with four-cylinder versions. They have been called Toyota New Global Architecture type transmissions, and alternately referred to as the “Direct Shift 8AT” eight-speed automatic transmission. This transmission was

Tasc-Tip-December-Figure-1---LFC-Valve-OE-Partial-Circuit-Diagram-1400