360 Touch the brake and no throttle until restart

Hi.

I recently brought the x-silverstone experience Blue 360 that been on and off sale since autumn last year – £25k one.

It’s now running quite well on startup, will run up to temp and moves revs ok.

If I press the brake pedal my gear selection changes for “-“ to “N” and I can shift to 1, 2 and R. As soon as letting of the pedal it reverts to “-“.

However, the moment the brake is pressed the throttle stops having and real effect of rpm – throttles won’t respond. If I release the brake pedal completely, I still get no throttle – and can only get it back by restarting her.


The rpm does sound like it’s moving a little on pedal press but the rev counter is frozen at idle and orange engine light comes on. it kinda feels in the car like your trying to move away with the handbrake on in gear on a manual - revs sorta held back.

If I try starting holding the brake pedal it won’t really start.

If I start her with no brake, don’t touch the gear selectors, revs fine, engine light out, touch brake pedal, no more rev and engine light back (though gbox then shows "N")

I have a Launch X431 mini. Connecting as a 360 this won’t connect to the right ECU – but the left shows…
- The P1675 Instrument Panel: CAN Line Timeout (B2) & P1632 F1 Gearbox CAN : CAN Line Timeout (B2)
- Gearbox gives P0720 Gearbox Output Revolutions, P0600 CAN error code & P1760 Brake Error.

As a 430 I can connect to both ECUs and see data…
- The Right bank gives P1674 Instrument Panel Timeout & P1672 Gearbox Timeout
- The Left gives P1655 CAN error Instrument Panel Timeout Lhb Intermittent Signal & P1632 CAN Messages Timeout from lhb gerbox ECU
- Gearbox gives P0720 Car Speed, P0600 CAN error code & P1760 Brake Switch.

When I got the car the brake pedal sensor had what we believe is the redundant clutch sensor plugged in and the brake sensor had a jumper wire plugged into it – removing the jumper allowed the throttle bodies to respond though gear selection would only show “-“.

The brake pedal sensor I cleaned, and it activates the brake lights and can be seen moving between on and off viewing live data on the TCU.

Battery light is also up to something. on startup it goes out but then comes back, flashes once, then stays on. Launch is seeing 14+ volts when running.

Any suggestions on how I might diagnose this further? I’m guessing the primary issue is the ECU to TCU coms and my iffy brake pedal issues are perhaps just the effect of the dicey comms? Also the instrument cluster was removed to hydro-dip - could something have been disturbed that might have these sortta symptoms?

Cheers! Jez.

 

Not really sure what you mean. Where is the clutch sensor positioned?

Do you have a 4 pin brake pedal sensor or an earlier 3 pin? The 4 pin has two sets of contacts (diagonal pairs). One is normally open, the other is normally closed. I believe this is for some kind of logic check and may require certain types of computers to match this setup. Maybe the redundant clutch sensor is a workaround for this?

You may be able to do wiring checks between the brake pedal and the computers.

You have so many errors, I'm not even sure where to start. Maybe you just have a battery issue? How old is it?

 

Looks like you have a masive CAN bus issue (bad contact or short somewhere).
The "-" on the gear display means that the instrument panel is no more receiving the selected gear through the CAN. This should not happen when pressing or releasing the brake pedal.
You should start by investigating the CAN bus wires. Most, if not all, the errors are linked to CAN (including the P1760 Brake switch, throttle response, ...).
Check the integrity of wires and termination resistors, search for possible shorts to ground or 12V when pushing or releasing the brake pedal, ...

 

Thanks both.

It's an earlier 3 pin. The car has two of these 3 pin connectors coming from the loom by the brake pedal. Someone, at some point, had plugged the redundant clutch one into the brake sensor rather than the brake one - and had also jammed a wire into the actually brake pedal sensor plug to trigger it - perhaps in trying to diagnose the issue i'm facing.

Good to know the "-" should not be apearing on brake press - as you suggest I'll go a hunting with the probe on the CAN and brake wiring.

Battery is not that old I believe - but it did sit in a barn for quite some time so I'll sitck a new one in just to be 100% and deploy the old one as dedicated to the QuickJack

again, many thanks.

 

Not sure how this is related to the CAN Bus, Eric. The (analogue) wiring from the brake pedal switch goes directly to the Suspension ECU, Brake ECU, brake lights, Left Motronic, Right Motronic and F1 TCU via splices. Having said that, I don't have a definition of code P1760.

Not sure how that would work. There is no point sending a brake signal down the clutch sensor wiring (unless the clutch wiring is being used until it reaches a certain plug, then rejoined with the brake wiring. The brake pedal switch relies on power being supplied to it. The clutch pedal needs a ground/earth. I'm not sure what kind of brake switch is required on UK cars (3 or 4 pin). What year is it? 1999 or 2000 and onwards?

I have wiring diagrams if you need to check the CAN busses and brake pedal wiring.

 

I think it was just plugged in in error. same connector. Car is a 99.

This was how it was when I got it...



/sorry meant to be a link to 30 seconds in - keeps turning it to embedded video link sorry.

I swapped to the correct connector and cleaned out the sensor switch (wasnt make a reliable contact) and from that point car had brake lights working on the pedal, see it activate on the Launch and throttle boddies happy.

That'd be very useful if it differs from the "360 spider wiring diagrams.pdf" that I have?

 

Ian, the brake switch status is also broadcasted on the CAN bus.
If the TCU does not receive valid CAN frames, it raises the P1760 code because it is not able to assess the consistency of the wired switch status and the broadcasted one.

 

The Ferrari diagrams show you which plugs/pins are connected to which plugs/pins. They don't really tell give you much of an overview like traditional wiring diagram. I've converted most of the Spider wiring diagram pdf into more traditional diagrams. The pdf is still useful for routing and plug locations.

Here's one of my more complex diagrams which shows the brake pedal switch wiring (3 pin version shown next to 14D)

https://www.dropbox.com/t/LjSEj8MqML4CwSZs

The brake switch (14D) and clutch switch (15D) are shown on the far right (around the middle). The wiring goes to plug 12D/19D then on to a number of splices.

I do have diagrams for the 1999 version, but there are a few unresolved issues. The fuseblocks (2G and 3G) behind the right hand seat seemed to be swapped around (vs the later Spider). I don't know if this is a labelling error or not.

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3G on both cars should have an empty relay slot in the upper right corner. Could you take a photo of yours to confirm the location?

 

Thanks, Eric. Just wondering what computers need the CAN Bus version. There seems to be hardwiring to the important ones. On cars with 4 pin brake pedal switches, the normally closed part of the switch only talks to the RH Motronic ECU. However, I don't know if the other computers need this data. This is a 1999 car, so I'm just wondering if later model Motronic ECUs have been fitted to this car and the ECU software hasn't been adjusted to match a 3 pin brake pedal switch.

Since comms with the RH Motronic ECU seems to faulty, I guess we should focus on CAN Bus wiring. Some of the CAN Bus wiring is shown in the diagram I posted in the previous message.

@71six Find instrument panel plug 6E in the diagram and follow the white & green wires. There is also a CAN Bus between the L & R Motronic ECUs (also green and white wires with a resistor in parallel).

 

Sorry, brain not attached to typing fingers. Excuse the grammar.

 

@Qavion thanks again for the wiring diagram - been super useful!

the issue seems to be the ABS/ASR ECU. With the brake pedal pressed the white CANBUS line coming from the unit into connector 2b/22b is sitcking out 12v down the white wire - i guess then messing up the canbus network and thus all my issues.

HTML:

<a href=https://www.youtube.com/shorts/WIKcjs8wjhI>small video of the issue</a>

the wiring diagram just shows the 22b output as 120 ohm and no refference to where the go...

... but if im right and its the ABS/ASR ecu then i suppose that doesnt matter really.

Just hope can be fixed as they seem very pricey!!!

 

Weird.

Yeah, I haven't got a full diagram for the CAN Bus, but you are right, the CAN Bus does go to the ABS/ASR ECU via plug 22B/2B.

Here's the brake diagram:

https://www.dropbox.com/t/MZtwtNwg3oifm2vA

 

If it was me I would replace the brake switch with correct one for car ( with proper install as per WSM) and also change the rear speed sensor on transmission

 

pulled the ABS unit - It's off to SinSpeed to get checked out... fingers crossed!!!

 

I was expecting there to be a wiring short somewhere. i.e. between the brake pedal wiring and the CAN Bus wiring.

With the ABS unit removed, can you activate the brake pedal switch* and see if the white wire gets 12 volts? (key on)

*Is it possible to activate the switch without disturbing the brake pedal? I don't know what pressing the brake pedal actually does with the ABS unit removed.

 

nope gets nothing on white wire at all. i get 12v into pin 14 on ABS (from brake pedal) but the green and white (pin 29 and 30) that go out of abs into connector 2b stay zero'd. the 2b plug is a few inchs from the main abs hookup and i was measuring voltage with this unplugged from the connector to dash so just a few inches of wire from the ABS/ASR plug - no shorts in wires of the connector block itself... thus the 11.5/12v in to the white pin 30 must be coming from the ABS unit itself is what i believe. Interesting to see what the say when hook it up on test bench.

 

(EDIT) Sorry, I misread your last message. If you saw my last response, ignore it.

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So you're saying you had the ABS plug and the 2B/22B plug disconnected and pushed the brake pedal, but no volts at 22B, thus eliminating the chance of a short on the 22B side of the CAN bus plug.

The ABS wiring and CAN Bus wiring do look fairly isolated anyway, with all that plastic sheathing... at least to the bulkhead. The wiring follows separate harnesses.

Your second check proved that there were no shorts in the ABS plug.

 

yup you got it - no 12v on the 22b side - but do get 12v on the white wire on the 2b side with pedal pushed.
the red wire into 1b (pin 14) from the brake pedal is 0 volt not pushed and 12v when pushed as i guess im going to expect.
so unless 12v is meant to be coming down the white wire its defo iffy abs unit - as say i dont see a short from pin 14 to to pin 30 (and into 2b) on the wiring harness itself.
love to know what the voltage is to both the pins on connector 2b... but i guess being canbus it should basically we the same as all the other green/white combos elsewhere right?

 

You would think so, although I'm not sure if the CAN Bus resistors affect the voltage. It may depend on how/where you measure the voltage (and what components are disconnected/connected at the time).

Voltages (as measured on an oscilloscope) should be from 1.5 to 3.5 volts (according to Google).

 

so crap news on my ABS from SinSpeed...

"...we have found that there are no loose wires in the connector, but there is clear evidence of water damage.
Unfortunately, the unit has failed the tests, and based on our findings, it appears to be faulty.
At this point, we are unable to proceed with a repair, as the damage is significant. Additionally, we are currently unable to source a replacement part."

So I guess my only option is a replacement unit. or run without ABS/ASR

 

Ugh.. thanks for the update.