power mode still/again

spinn360 · #1 04-09-2006, 11:59 AM

So the car keeps going into power mode. Not just the power light coming on. but the actuall shift points changing to about 5 grand. I thought the tps was the culprit and it was replaced with a used one. took a while to set it as the butterfly valve wasnt closing all the way. ( I had to clean it

) Then got it set to .5v. Car ran good for about 1 week. then power mode started coming on. More frequently now. I am thinking it is the TCU. I paid for one, and its supposed to be on the way soon(I hope). the power mode came on yesterday when I was stopped at a stop light, at a freaking stop light! No gas applied, no change in throttle position!

I can turn it off when I am on the highway by turning the cruise control on, but when I do that, the tranny goes to 3rd gear even at 70 mph. When I am in town I can stop the power mode from coming on by pushing the manual button and shifting from 1st to 2nd gears manually. I am not sure but I thought I would post this to see if anyone else has had this prob. Or if anyone knows how to fix this. I am set at a very tight budget right now and I cant afford anything over 100 dollars so, I cant replace the TPS with a new one(besides the fact that I dont believe this would do anything). Someday maybe I will put the 5mt in but that will have to be further down the road. God I hate Automatics.

Please if anyone can help that would be great.

intelisevil · #2 04-09-2006, 02:56 PM

I hope you get your problems sorted out. With all of the 5-speeds floating around, there have to be a lot cheap TCUs available.

With all of the SVXs out here in Oregon, I really wish we had a TomsSVX in the neighborhood!

Dan

b3lha · #3 04-09-2006, 04:28 PM

Measure the voltage of the white wire at pin b8 of the TCU. This is the wire from the TPS to the TCU. With the throttle fully closed it should be 4.0 to 4.8 volts. At WOT, it should be somewhere between 0.7 and 1.7 volts. Go for a drive with the voltmeter connected and see what the voltage is when your spurious power mode occurs.

If power mode activates while the voltage is >1.7 volts then the TCU is at fault, otherwise the TCU is just doing what it is told.

oab_au · #4 04-09-2006, 04:55 PM

Could be the ATF temperature sensor in the trans, that is reading wrong. It will put it in Power Mode, to cool the ATF.

Harvey.

Trevor · #5 04-09-2006, 07:45 PM

Quote:

Originally Posted by oab_au

Could be the ATF temperature sensor in the trans, that is reading wrong. It will put it in Power Mode, to cool the ATF.

Harvey.

Exactly which and what circutry will activate this feature, which I can not find refered to elsewhere. ?

Are you saying that this will raise the shift points at all degrees of throttle opening and will as a result, lower the transmission fluid temparature to a worthwhile degree ? If so, those with Power Mode switch could keep this mode in constant operation to advantage. It is strange that this idea has not been previously been brought up here.

Trevor.

SomethingElse · #6 04-09-2006, 08:45 PM

its probably some kinds of thermistor. resistance changes with tempreture..just like a coolant temp sensor. oh well no more automatic so i dont have to worry about it

TomsSVX · #7 04-10-2006, 06:34 PM

Quote:

Originally Posted by oab_au

Could be the ATF temperature sensor in the trans, that is reading wrong. It will put it in Power Mode, to cool the ATF.

Harvey.

My understanding was that the temp sensor was to serve 2 functions. Allowing the trans to stay out of 4th gear until the temo reached 50*F and then keepin the TC from locking until it reach 150*F(I think). Maybe this is what you were thinking? I have never heard of the temp sensor having anything to do with the power mode. Infact you can still engage power mode when it is freezing cold or fully warm.

Tom

SomethingElse · #8 04-10-2006, 08:12 PM

I dont have a garden path

Trevor · #9 04-15-2006, 01:16 AM

Quote:

Originally Posted by oab_au

Could be the ATF temperature sensor in the trans, that is reading wrong. It will put it in Power Mode, to cool the ATF.

Harvey.

Trevor ---- Are you saying that this will raise the shift points at all degrees of throttle opening and will as a result, lower the transmission fluid temparature to a worthwhile degree ? If so, those with Power Mode switch could keep this mode in constant operation to advantage. It is strange that this idea has not been previously been brought up here.

Harvey this is an interesting concept you have outlined and I had hoped for a reply to the above, as possible advantages of use to members are indicated.

I always drive in third within city limts in order to prevent the transmission from hunting up and down in and out of drive. Using power mode would move up the shift points, as I see it, only at full full throttle. But there should be no hunting betewen low and second. There is reason for further investigation, in order to possibly utilise this feature as a means of protecting the transmission against overheating. Circuitry must exist involving the ATF temperature sensor and it may be possible to incorporate some form of overide switch.

Others will be interested in this prospect and your reply will be appreciated, Trevor.

SSSVX · #10 04-15-2006, 01:55 AM

Quote:

Originally Posted by Trevor

Using power mode would move up the shift points, as I see it, only at full full throttle.

When the power mode is on, the shift point will go higher. But it's not necessary when at full throttle, I could activate my power mode anytime as I wish, the way to do that is quickly put down some gas on the pedal no matter how much, as it's quick enough the power mode will be activated...

PS: I haven't done full throttle on my yellow one after the second swap...trying to take it easy first. (only 300miles driven) I tested it the other night...I only quickly moved down my throttle about 1/3, the power mode could raise my shift point at 5000rpm of the second gear.

Spinn360, as you said, your power mode will randomly activate. But could you activate your power mode when you want to?

b3lha · #11 04-15-2006, 03:49 AM

Quote:

Originally Posted by Trevor

If so, those with Power Mode switch could keep this mode in constant operation to advantage. It is strange that this idea has not been previously been brought up here.

It has been brought up before. I remember this being discussed in the Euro forum some time ago, though I can't find the thread at present.

I keep the power switch on all the time except during motorway cruising. I've found that it does not seem to effect the overall fuel economy and I enjoy the more responsive feel. I also use position 3 a lot and hopefully these measures taken together will extend the life of the transmission.

There are so few of us with JDM cars that the idea is irrelevant to most people. I recently suggested that someone with a USDM SVX should try connecting a switch in the same way that the JDM one is connected and see if it works.

Does power mode definitely stop the TC from locking? As Earthworm said, that could be a downside due to the extra heat generated. I can never really tell whether mine is locked or not, but the SVX is always very responsive, power mode or not. When I press the pedal, the acceleration is *instant*. On all other automatics I've driven, (mostly Mercedes, but also Jaguar, Vauxhall, Peugeot and a few others), when I press the pedal, the rev counter climbs and then a few seconds pass before the car starts to accelerate.

Phil.