Here is E10 It's under the drivers dash, on the tunnel side. From here the wires go direct to the lamps in the dash. Funny bit is that the bottom part of the connect is the side that goes to the dash. Image Unavailable, Please Login
This is a simple drawing of the cct. Now I can find E10 and E26, but E11/E29 escapes me for the moment. and the WSM schematic looks wrong So does anyone know where it's hiding ? Routing Clearly the work of a deranged person. From the Airbag ECU.... it splits into the 2 Airbag feeds and a diagnostic feed. the remaining main part of the cable carries on and gores up and over behind the glove box towards the outer wall of the the passenger side. Here it seems to merge into another main cable. I can not access it yet - would need to remove glove box It then seems to head toward the fuse/relay panel. From the Dash..... Direct wires from lamps to E10 From the otherside of E10, it goes up and behind the dash and over towards the A pillar. From here it T's, one side routes back over the dash and towards the centre. The other side of the T, heads off above the pedals. Image Unavailable, Please Login
Observation Even with E26 disconnected, (=AB ECU is not connected) The dash lamp is ON. This implies there is some path to GND that is illuminating the lamp. Testing If I disconnect 10F, so removing the Dash from the equation. I can buzz from E26 pin (lamp - pink wire) to the E10 pink wire pin. = so the connection is good. Here's the problem..... It also measures a 5ohm path the GND. I wonder this..... Is there actually a resister to gnd, as this would then illuminate the lamp in the event the ECU lost power/failed/disconnected. If that is true, then... What value is the resister? Where the hell is it ?
Qavion Your investigation is correct - once I took the lower steering column cover off and your description it then makes sense.
There is probably a solid state switch in the ECU which closes when power is lost, putting an earth on the lamp. I don't think you'd (normally) get the lamp lighting up if the ECU was completely disconnected. It may not be a resistor, but a less than perfect short to ground which just happens to be around 5 ohms. Airbag harnesses are usually in their own yellow sheathing, so the short may be to another airbag wire. The other wire may have the 5 ohms in its circuit. I hope the 5 ohms isn't the airbag squib and you're putting a voltage on that with your ohmmeter *or grey-green, depending on which section of the wiring is affected. It's a pity you can't find that connector, it would help you isolate the problem. I think it's pure laziness that this wasn't fixed properly by the mechanics.
With the ECU plug disconnected and the instrument panel plug disconnected, can you get continuity between the pink wire and any of the other ECU harness wires? (there shouldn't be any continuity).
SOLVED ! But first some interesting bits... Connector The connector that connects to the ECU is a cleaver bugger. When not connected to the ECU, there is an extra set of contacts in the connector that then short together certain pins. eg pin 11 and 12 which is how the lamp gets switched on when the cable is unplugged. So if you are buzzing out a wiring issue, be aware of this. E11/E29 E11 is just 9" or so up the cable from the main ECU connector. It's odd, as it looks like the airbag connector in that it is; a) 2 wire only (not 3) b) very yellow Now to the solution.... drum roll.... long pregnant pause (for dramatic effect)…. Some bastard had swapped the bulbs between the position for the Handbrake and the Airbag, and also removed the airbag bulb in the dash. So handbrake on = airbag light on / and vice-versa So simple and yet so i r r I t a t i n g. I now have a properly working airbag system
Ros- Good sleuthing. An old Ferrari tech once told me the biggest problem with Ferraris was gold-plated screwdrivers used by amateur mechanics. Do not think the gold had anything to do with it.
Yet another error in the WSM diagrams. So something like this, perhaps (with the yellow/red wire wire going directly to the OBD2 port) F456 Airbag circuit And you saved yourself a few thousand pounds. Ros, on another positive note... I fixed my home plumbing problem
Next Problem = Brake Failure Lamp is on, and there is no power assistance. What would be the first things to test for diagnosing this one ?
Does she have ATE or Teves brakes? All our 5.2 456s had ATE, but not sure about the ROW. Hydraulic assist on one, vacuum on the other.
Is this something recent, Ros? Sounds like you've lost your speed signal. That ties in with your rear spoiler problem. Right rear wheelspeed sensor failure? Do you also have an engine check light and a suspension light? Your window ECU also uses the speed signal to keep the window snug on the seals at higher speeds. Did you find the white-yellow wire on your spoiler ECU? (EDIT: I thought you might have blown fuse 20 in the footwell, as that powers the power steering module, but fuse 20 powers all the instruments, too)
The only warning lamp is the BRAKE one. All other systems (except spoiler) are working. I'll report later today - going to investigate now.
Perhaps individual faults, then. I hope your steering problem is easier to fix than DrivenHK's problem: https://www.ferrarichat.com/forum/threads/456-power-steering-trouble-shooting.605029/#post-146818742
Spoiler fairly sure that this is the motor issue, (the wipers internally get covered in crap). so no issue - can repair that easily. Brake Symptoms Brake pedal takes a lot of pressure to press and can barely stop the car. Pedal does not move very much before getting very hard. Pump/Accumulator If I apply power directly, I can hear the motor run. Funny, I let it run for 30sec. thinking it will build some pressure But yet my brake pedal was still very hard to press (no change) ABS ECU I assume the ECU, mounted just up a little from the Pump/Accumulator is indeed the ABS ECU ? ? ? ? It has 2 pony tail wires that have protective covers a) 2 pins b) 3 pins I assumed (b) was the diagnostic cable. I connected Leonardo, tried the ABS diagnostic but it would not communicate. Does that mean... a) that the ECU is for something else. b) the Leonardo does not have the right protocol c) the ECU is not working Any suggestions on how to test ?
Ros- See if this helps on the brakes. It came with a Ford, but has a lot of good data on the Teves system. The second came from Alfa Romeo.
Unfortunately, all the manuals and wiring diagrams I currently have seem to be applicable to ATE system, not Teves, so disregard the wiring link I provided earlier in personal mail ECU location, fuses, relays, etc, may be completely different on your car. The ATE ECU is in the cabin. Can you see any fuseholders near the hydraulic unit? The ATE system has fuses and relays near the hydraulic unit, but also a maxi-fuse in the engine bay (RHS) for the pump motor.
Update.... The WSM (as bad as it is) seems fairly correct on the position of things. So the ECU above the pump/accumulator is the TEVES - ABS On the inner wing under a black plastic cover are the 4 relays and fuses that seem to control the main pump and ABS pump power. The Brake Warning lamp according the WSM and Qavion's drawing is driven by 4 inputs. a) ABS ECU b) Left front wear c) Right front wear d) Pressure Sensor So I'm at a loss to know why it's on - but that is a secondary problem I feel. ABS If the ABS has a fault the ABS lamp should be on or flashing out the error code. Test 1. ABS light flash when IGN is turned on and goes out = seems correct. ABS Button = when pushed the ABS lamp lights up = seems correct Test 2 Tried power to the pump and it pumps. Test 3 Tested the 4 relays and fuses = all working Test 4 Cracked open (1/2 turn) the feed from the pump into the Master Cylinder. Brake fluid starts to leak out - clearly under pressure. It was very much like "white mousse" and there was a lot of bubbles - so not sure if the change in pressure does that to brake fluid. I wonder if the accumulator has failed ? Test 5 Pump then runs on it's own, due to Test 4 dropping pressure. Test 6 Cracked open the 2 brake pipes that go/return to the ABS Pressed brake pedal A little bit of fluid. Theory So my theory is that like another FChat member, something has gone wrong on the Pressure side of the Master Cylinder. Action So I now have the big plastic reservoir off. That little screw underneath was a bugger to get out. Now the two T50 screws appear to have been glued/welded/fused by god into the rest of the assembly. and that's as far as I got. Will try to find a way to drive the torx bit harder into the head of the screw.
Look in the cross reference thread (stickied at the top of this subforum). Pretty sure someone has posted an equivalent.
I thought it might be set up similarly to the F355/F348 Teves system, but there are 3 relays and a diode box, not 4 relays. Does your car have an empty fuse slot to be used when diagnosing the system? Normally, there should not be a fuse in this slot. I can't remember what happens if you leave the fuse in there. It may leave the light on. Best to ask the 348/355 forum if no one here knows. On the 355 and 348, the test fuse puts an earth on pin 26 of the ECU. It's either a 5 or 10 amp fuse. The regular ABS fuses are 3 or 30amps.
Jaguar had the Teves system, but the parts are getting rarer and rarer. Superformance offer a replacement accumulator, but there were height problems with that on the 355 (may not be an issue on the 456). http://www.superformance.co.uk/v12m/brakes.html ... £389.24 plus VAT On the 348/355 forum, they are getting very creative with substitute parts for the Teves system.
