'98 V70 T5, resetting gearbox shift points?

[papariccardo]

Hi, my T5 shifts very high in RPM in first, at low foot pressure it shifts around 3-3500 rpm, moderate acceleration can leave it in first until redline. All this while in economy mode. Any thing I can do to reset this? Thanks all

[jose456891]

I have never heard of this, never.

I reckon that there is another issue in you transmission completely unrelated to the TCM's shift points. As per Volvo's own literature I have read that there is a learning "sequence" in volatile memory of the TCM. In short what it means is that the TCM can be reset by plugging it out of the car for a little while 6-12 hrs?

I heavily doubt that the red line issue is related to the TCM's shift points.

Weird...but your problem might be to lazy solenoids/dirty ATF.

RSPI, Lee please chime in, as this is a rather interesting complication.

[papariccardo]

Thanks, I thought it might be that, but it was without a battery for 2 weeks, and the fault remained when the car was refired. I drove leniently for a week or more, and still have the same fault. ATF is fresh. Nothing shows up on OBD-II reader.

[jblackburn]

AC on? Mine does that in the summer.

[jose456891]

TCM's rarely go haywire, but it might be of service is you borrowed one from a friend or junkyard. I don't know if your ASIN TCM is mated to the ECM in your car, but its worth a shot. A better option is to get a VIDA or a VAG-COM cable and see if the TCM itself has any codes.

Let me dig into the literature and see if there is procedure to force a "re-learn" on the TCM....

Can't find it....I'm reading old material for AISIN AW50-42LE, Motronic 4.3 for a 1995 850. So that may be why.

If you have a AW50-42LE transmission here are the shift points. Please note that AC does not affect the shift points:

SHIFT SPEED SPECIFICATIONS
SHIFT SPEED SPECIFICATIONS (2.3L TURBO) (1)
Application MPH
Economy Mode
1st-2nd ............................................. 25
2nd-3rd ............................................. 51
3rd-4th ............................................. 76
4th-3rd ............................................. 53
3rd-2nd ............................................. 31
2nd-1st ............................................. 16
Sport Mode
1st-2nd ............................................. 36
2nd-3rd ............................................. 69
3rd-4th ............................................ 106
4th-3rd ............................................. 62
3rd-2nd ............................................. 47
2nd-1st ............................................. 26
(1) - With shift lever in "D" position and throttle valve
open 60 percent.


SHIFT SPEED SPECIFICATIONS (2.4L NON-TURBO) (1)
Application MPH
Economy Mode
1st-2nd ............................................. 24
2nd-3rd ............................................. 48
3rd-4th ............................................. 75
4th-3rd ............................................. 60
3rd-2nd ............................................. 36
2nd-1st ............................................. 15
Sport Mode
1st-2nd ............................................. 35
2nd-3rd ............................................. 68
3rd-4th ............................................ 101
4th-3rd ............................................. 86
3rd-2nd ............................................. 57
2nd-1st ............................................. 24
(1) - With shift lever in "D" position and throttle valve
open 60 percent.


LOCK-UP SPEED SPECIFICATIONS
LOCK-UP SPEED SPECIFICATIONS (2.3L TURBO) (1) (2) (3)
Application MPH
Economy & Sport Mode
Lock-Up ON - 4th Gear .............................. 129
Lock-Up OFF - 4th Gear ............................. 124
(1) - With shift lever in "D" position and throttle valve
open 60 percent.
(2) - Lock-up does not occur in 2nd gear until fluid temperature exceeds 239 F (115 C).
(3) - Lock-up occurs in 4th gear only.

LOCK-UP SPEED SPECIFICATIONS (2.4L NON-TURBO) (1) (2)
Application
Economy Mode
Lock-Up ON
MPH
2nd Gear .......................................... 25
3rd Gear .......................................... 49
4th Gear .......................................... 73
Lock-Up OFF
2nd Gear .......................................... 23
3rd Gear .......................................... 44
4th Gear .......................................... 68
Sport Mode
Lock-Up ON
2nd Gear .......................................... 35
3rd Gear .......................................... 65
4th Gear .......................................... 96
Lock-Up OFF
2nd Gear .......................................... 33
3rd Gear .......................................... 60
4th Gear .......................................... 90
(1) - With shift lever in "D" position and throttle valve
open 60 percent.
(2) - Lock-up does not occur in 2nd gear until fluid temperature exceeds 239 F (115 C).

[jblackburn]

Please note that AC does not affect the shift points:

Unless, as a driver, you are stepping harder on the pedal than you would normally be to make up for the lost power. Especially once the intercooler is heatsoaked from traffic and the condensor/radiator sandwiched to it

My car is weak below 3000 RPM with the AC on, so I guess tends to shift high to accelerate at what seems a normal pace to the driver. I always felt like I wasn't stepping on it as much as the high shifts made it seem like. A shift out of 1st at 4000+ RPM was not uncommon for me in summer months, whereas without AC on, it would normally be 3000 or so.

[jose456891]

So perhaps the shift points are mapped to engine load more than RPM's?

That would suggest that the OP is suffering from a heavy load/low power? That would make a lot more sense than to have static RPM shift points. Perhaps the TCM is mapped to available power output?

OP: When was the last time you performed stage 0 maintenance?

[jimmy57]

98 tcm is plug n play between like cars.
The adaptives are not as smart as you may think. The adaptation is for shift completion time. Shift scheduling is not adaptive. Scheduling is a function of throttle position and engine load weighted plotted to vehicle speed. The TCM does not learn YOU. The TCM learns to control STH (pressure regulating solenoid) to get the shift time within target. Since there is no pressure sensor the feedback for adaptation is solely shift time. The single thing that approaches learning YOU is if you are on the ball enough to let up on throttle every time the trans shifts then the TCM adapting is different than for someone with a steady throttle foot during shifts. Adaptation on the 5 and 6 speeds is also for the linear shift solenoids as those transmissions use a different shift control strategy with more solenoids directly controlling fluid apply pressure. 4 speeds use shift solenoids controlling valves in the valve body that in turn sequence the fluid pressure.

I would count shifts and make sure that you are getting every gear. It could be missing 2nd and going to 3rd. I would expect a fault code in TCM but that is not always true.

[papariccardo]

That's how I drive it, with a tiny back-off the "jandal" when I want it to shift, which tends to bring the shift in then. It just seems higher than any of my 850 T5s - although they have peak torque at lower RPMs, that probably is why. Thanks for the useful advice guys!

[rspi]

Just read this post. Under normal throttle, which I am usually a little light on it, I'm shifting around 2,300 to 2,500 rpms. If you are going above 4,000 rpms under normal pedal effort, I would think that you have an issue with your throttle body switch, linkage, cable, or something in that area/system. If the tranny is hitting all of the gears I would hope it is ok.

The TCM's prior to '99 are not mated to the ECM's. Also, that "car learn your driving style" stuff didn't start until they dropped the E - S - W buttons. That system was pretty passive and had suttle changes in the shift points. From what I am reading, your car is shifting like it thinks your throttle position is near WOT.

If you can get your hands on a scanner that can read live data, see if you can read where the computer thinks the throttle position is. If you are at 20% and it is reporting 80%, there lies your problem.

In the mean time, check your throttle cable linkage to make sure it's not hung up on something.