430 430 challenge can bus issue

Working on a 430 challenge. issue began with losing some of the data on the marelli dash, engine losing power, ASR turning off. Scan found no communication with cluster or Abs unit, P0600 Can faulty in the trans, no faults in the engine modules. Fuses are good, check of C can found 60 ohm resistance, 2.5 volts high, 2.3v low. Need accurate diagram for challenge car as OBD connector has the B can wires in #6 and #14, not white and green C can wires as shown in the coupe diagram. Have disconnected all units one by one , still no bus communication, suspect ecms and trans communicating over K diag wire.

 

Issue has now progressed to the engine no longer starting, no faults in ecms,

 

Are you sure your battery/alternator are ok? The CAN Bus seem to be one of the first things to fail when power is an issue.

Your general CAN Bus wiring checks seem ok, so if there is a CAN Bus issue, it should only be in the individual ECUs (CAN Bus transmitter/receivers).

Does the OBD port have green and white wires on any of the pins? Most (if not all) green wires are connected to each other. Most (if not all) white wires are connected to each other. If you run out of ideas, can you check wiring continuity between the OBD port and the faulty devices (green to green and white to white).

 

Thank you for your assistance. Battery and alternator are good. The can bus layout on these Ferrari vehicles are nothing like the wiring diagram indicates. No green and white wires. Terminals 6 and 14 have white/pink and black/pink. These traced to the 8 pin harness on the cluster. The green and white of the C bus go into the 12 pin connector on the cluster. Test of C bus with scope shows a normal bus operation. 2.5v high, 2.3 v low with normal waves appearing. Did not scope the OBD as my scope acted up, I think due to hot conditions in the shop, but with switch on have 0.07 on one bus wire and 4.95 on the other wire. Have a 360 here in the shop. It has 0.07 on one side and 10.5 on the other. Wire color there is also not green and white, but not the same as the challenge car. As far as the no start condition, have no fuel pump activation, I suspect tied to the can bus issue not allowing relay to engage. The 430 coupe diagram is so much different than the real world challenge car. I was suspecting the cluster as the issue, Dont really know. This morning i disconnected the cluster completely. i could still talk to the ecms and transmission though some Ferrari magic. Have a California and a 488 here also, going to check the OBD outputs on those as well to begin developing a database.

 

As a side note, the wiring diagrams show the B can wires as being in OBD connector ports 1 and 9. nothing there.

 

As you discovered, there is no CAN bus connected to the 360 OBD port.

Do you have cranking? I assume it has no immobiliser?

Does the Challenge have an inertia switch? Are there any simple toggle switches for cutting off fuel on this car?

 

I have cranking, I do have a challenge car service manual that shows a immobilizer relay. No inertia switch I can find. Check of this relay found activation power coming from the right ecm with the key on. There is nothing on the 30 power terminal coming into the relay. according to the coupe diagram it should be coming from terminal 43 of right ecm, however, that wire is the wrong color and does not ohm out to the relay. Sure wish I could find a true challenge car diagram. so many things different.

 

I'm not sure why pin 30 should be provided with power from the ECM. Usually (pin 30) power for relays comes from the key, the battery or from other relays. Usually ECMs provide grounds, unless it is a small voltage for a sensor (e.g. 5 volts).

Maybe time to break out the wire tracker

 

What I've been doing recently is putting a low wattage test lamp on the coil contacts of ECU-controlled relay sockets and seeing if it lights up during cranking. i.e. 12volt/50mV lamp with legs long enough to go between the socket sockets. The low wattage lamp doesn't put any strain on the ECU internals (and simulates a coil, so that the ECU doesn't throw up a fault code).

On earlier Ferrari models, the Motronic power relay provides power to the fuel relay coil and the ECU provides the ground.

Would you have a chart for the, say, the relays and fuse behind the right hand seat? Is it like a regular 430 with PDR & PDF numbering?

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The relay and fuse boxes all look the same as the regular 430. Most all spots have relays, I find this kinda strange as so many systems are missing from a race car. Even the ABS unit is unique. Only has a 29 pin connector. I agree, time to trace and create my own wiring diagram. What would be the best tracer tool in your opinion.

 

When you say immobiliser relay, do you mean PDR1? You mentioned pin 43.

Here's the Scud diagram:

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It's actually a pulsed data signal going from pin 30 to ECU to unlock the ECU. The ECU then sends a signal (from pin 18) to the relay (pin 85) to energize the relay. As far as I can see, the signal from the Immobiliser ECU is no longer needed until you turn off the car. With the relay energised, the OBD system can talk to the RH ECU.

Perhaps the signal from the relay is still going to the RH ECU, but to a different pin. What you could do is use something like the tracker below to inject a signal on pin 30 of the relay and then probe around the RH ECU harness for the signal from the tracker.

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It's just a cheap tracker. Unfortunately, I can't remember the name of it.

It might save you probing all 121 pins with your ohmmeter.

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But a good way to find out if the immobiliser is unlocked is to simply see if your low speed fuel relay is turning on (PDR8).

Just use the 12 volt 50mA lamp on the coil pins of the pump relay socket (relay removed).

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Or you may be able to hear/feel the relay click when cranking the engine (relay inserted).

 

That is the relay. With the ignition switch flipped on there is power and ground on pins 1 and 2 . With the RH ecm disconnected There is no longer power supplied to pin 1. And check between pin 3 and 43 has no continuity. Getting a tracer coming.

 

If just with ignition power, then I assume the immobiliser has already been disabled (if my earlier assumption is correct). That's one good sign. An energised relay should allow your scanner to talk to the ECU, at least through the OBD2 network (not necessarily through the C CAN Bus).

So, it sounds like all the relay wiring is good. You may not need the tracker just yet, unless you really want to know which ECU pin the relay wiring goes to.

The ECU sounds like it's unlocking, so you just have to confirm that the ECU is sending all the right signals to the other boxes and relays (including the fuel relays).

 

I noticed on the coupe 430 wiring diagram, section fd0101, in the B can wiring that there are very faint numbers visible at the obd connector that say 6 and 14. I wonder if these denote challenge car wiring. Not there in the C can diagram, however, faint numbers exist at the cluster connection, cant make those out. I am beginning to think the fuse and relays listed in the challenge WSM are just there in the factory harness and do not control things.

 

Possibly, but I think it would be strange to have relays fitted in blank spots on the car itself.

Have you located the Immobiliser ECU? Looking at photos of Challenges, I don't even see a slot for an ignition key.

If you can't put a key anywhere, how does the immobiliser antenna sense the key in the ignition? Have you located the Immobiliser ECU under the dash near the base of the steering column? Does it have anything on connector A (antenna plug)?

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The Challenge parts manual doesn't even show an immobiliser.

 

I would agree that the challenge should just operate on an immobilizer delete setup for the ecu, however, these things have the relay 183662. That relay has power and ground with the ignition switch flipped, activating the relay. have a led test light that shows power and ground to test and nothing appears on the other legs of the relay. Is any signal sent readable or only seen on a scope? I can talk to each ecm, no faults found, however, there is no ground signal sent from pin 65 on the right ecm to the PDR8 relay activating the pump relay. Have not tested the left side, but I am sure the right ecm turns on the left ecm immobilizer system to allow pump operation. Seems just like you didnt press the magic button on the key properly before starting.

 

Do you have the padlock symbol on the cluster?

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The OBD2 port should be linked to the R ECU with the relay energised. It's for data, so I'm not sure if you'd see anything on a multimeter.

 

This thing has the magnetti data aquisition dash installed. That appears to be tied to the B can of the car so no symbols available. continued checking of the PDR1 relay found at the moment of ignition turn on approx 100mv then nothing. check of the 30 and 87 pins then found approx 11.5 volts on both with meter, but this will not light up the led test light. hit the start button and boom, she started. missing gear indicator, fuel oil temp on the dash. Shut off and started again. Then shut off master switch, waited a few and tried again. Will not start. Right ecm not activating fuel pump relay. I am now switching to diag of the loss of can bus as the likely cause. I can always talk to both ecms when connected and the trans. Ecms say no faults. I disconnect the car side connector on right ecm and check faults. No faults in left ecm, seems strange. Hard fault in trans for p0600, can issue. Disconnected the car side of the trans ecm. Left the ecm disconnected also. Scan now finds communication with the cluster showing faults for can bus, abs, various engine readings. Tries to duplicate the cluster communication unsuccessful. Disconnect the abs,now I have cluster comm. Keep in mind I can never comm with the abs unit.

 

I am beginning to suspect I have internal issues with the right ecm.

 

Which pin/s did you get the 100mv on?

If you short out pins 30 and 87 on the relay and the car starts, then that might mean the immobiliser isn't required to unlock the RH ECU. There may be a code because the ECU can't see the coil of the relay (with the relay removed).

Sounds feasable. Have you tried swapping the ECUs?

The WSM says that vehicle speed (from the ABS) is used for spark timing, but I don't know how critical it is.