Hello all. I have a F355 '96 with the F1 Transmission. The car doesnt shift gears at all through the paddles. It also does not display the current gear in the gear indicator and just shows 2 flat lines. I have the SD1 scan tool with the software and I have read the codes. Display control error is present. It says that there is a short circuit to VBAT. The SD1 scan tool displays various tests you can perform for each error code and I have checked them all. Under the Short Circuit to battery +ve test it tells you to check the voltage between pin 25 and 39 of the TCU. I also have the 55 way interconnector. It states that 'voltage between pin 25 and 39 should be other than 12v'. I don't understand if that means the voltage should be <12v or 0v. I'm guessing it should be <12v. But it displays 0v in my case between the 2pins. I have removed both seats and the carpets and checked every single wire between the TCU and the instrument cluster gear display and also all the wires going up to the actuator and F1 pump assy. All wires are completely intact. Through the SD1 tool I can shift all gears and also reverse. Just doesn't seem to work through the paddles. I have also replaced the gear display/ water tempt assy. with a brand new one, the digitek controller beside the ECU that seems to be connected to the TCU and also the clutch position sensor. The car has just done 2k kms so far in all these years. It is barely used. I have also checked the connector at the actuator. Any and all help is greatly appreciated. Thank you.
If you wait a while, @Qavion may come on and tell you what the voltage at that pin is supposed to be. My pure guess is it should be 0V and not 10-12V.
Thank you for the reply. I will for however long needed. This is what the test states. Image Unavailable, Please Login
12V is normally the pull-up voltage for an output pin with an open-drain or open-collector transistor. If you see 12V, that pin is shorted to something close to supply voltage. If your car is not running, it's very possible that the output of a power controlling relay is at 10V instead of 12V, so that is probably a fault. I would look to find a possible short for that pin.
Thanks for the info. I'll have to pull out the dashboard as well now to check the remainder of the harness that runs behind it to the instrument cluster. I'll check for this dreaded short and hopefully find it quick. Already pulled apart 80% of the interior. Dashboard is all that's left. So according to you there shouldn't be any voltage in that pin or something around 5v makes sense?
Sorry, I have no information on what should be on the line going to the F1 indicator (pin 25). Pin 39 is just a chassis earth. All I can suggest is disconnect the TCU and the gauge and see if there is a stray voltage on the pin 25 wire (grey/red). If that is the case, there is an 18 pin "dashboard system" connector between the TCU and the gauge.... disconnect that and repeat the stray voltage check. Of course, there is a possibility that the 10 volts is coming from another wire on the TCU harness, so you may not see the 10 volts if you disconnect the TCU. Wiring diagram here: https://www.dropbox.com/t/tAsWP0MVyYXQDFaJ I don't exactly know where the dashboard system connector is. If you find it, maybe you could photograph it, showing the location?
Since the paddles do not work have you tried starting the car in automatic mode with the brake pressed if it’s stuck in gear It should select first if the car starts in neutral and all the doors and bonnets are closed and you select automatic When you push on the brake and hold it it should select first gear this would indicate that you have a short in the paddle controls and it is sticking as if you are holding one of the paddles in
After reading your other posts you originally had a fluid leak from the actuator Did you fix this? Did you bleed the system? Properly? This could be air
If this was all done and it was working for a while then check to see if my process works for when car is started in neutral this may tell us the paddles are shorted
Take a look at the micro switches on the paddles. I had one fail and it would not shift down. I was driving and the car simply downshifted on it's own of course. You don't have that luxury to find out.
That’s what I saw as well thinking it could have shorted but if the paddles are not working the display knows I think, maybe, Need to review I don’t understand the fault code but it would not be the first time.
(EDIT) I can't see a connection between the SD1 fault shown and the paddles. I thought I'd found a possible link, but I got my wires crossed. There is a 12 volt wire which runs next to the wire coming from TCU pin 25 (at the Dashboard System Connector). Image Unavailable, Please Login Maybe a short between these two wires would cause 10 volts to appear on the pin 25 wire.
Sorry for the late reply. It was past 11:30pm for me. Thank you everyone for so much information. I will definitely check out everything. As for taz355 the car starts up normally even with the 2 dashes on the display. I will try out the procedure you told me to try to put it in first. Yes I had a fluid leak but I got that rectified and I also bled it through the SD1. But this display problem with the 2 dashes has been present for a very long time now. I haven't been able to drive the car for months. I suspect you are right about the paddles. I was checking and comparing voltages between the 2 paddles and my downshift paddle was missing a 5v in the same pin as compared to the upshift paddle. So I had decided to run through the tests provided by SD1 but all that seemed fine. So I assumed I'm not getting 5v because maybe the car wasn't in gear and hence didn't need to be ready to select a lower gear? But now that you've mentioned it could be a stuck paddle I'll revisit that entire area. Also I've checked the functionality of all the transmission related switches by looking at the live graphs and all switches seem to be working fine(the graphs moves up and down in the SD1 when I actuate any of the switches and paddles). Even though that's the case do you still think my paddles could be faulty? Thank you for everything.
This is really great information. Thank you sir. I will check this out again. Also where do you get the wiring diagrams? I have the original 3volume manuals but I just can't find anything where it mentions what values are present at what pins.
Also wanted to mention that is it normal for not being able to perform the PIS calibration procedure due to this fault?
I have checked the wiring coming from the TCU up to the connector under the reverse shifter assembly. I'll be taking out the dash to check the rest that you have mentioned and according to the wiring diagram you have provided. I will definitely photograph it and post it here. Thank you sir for all the information. If anything else comes to your mind please do share. I'll update this thread on what I find shortly.
The Dashboard System connector may look something like this... Image Unavailable, Please Login ... but where it is in relation to everything else, I don't know. Maybe forward of the centre console?
Yeah that connector is definitely under the centre console where the reverse switch is placed. I'll check the voltages and also if there's any continuity between the pins.
I'm not sure if the voltage will be present on pin 5 of the Dashboard System Connector with the TCU disconnected. The TCU energises the TCU power relay. Maybe you could do a continuity check between the power relay socket and the grey/red wire (to see if there is a short between the wires). i.e. with the TCU disconnected for safety. Image Unavailable, Please Login
Sure will do. It's one of the 3 relays that sit next to the TCU right? I know that one of them is for the TCU, another is for the F1 pump but I don't know what the third is for.
Image Unavailable, Please Login According to the parts manual: #12 is the reverse gear (lights) relay #13 is the pump relay #14 is the TCU power relay
