348 diagnostic system retro fit and fault diagnosis.

During the driving season this year my car had suffered from an occasional misfire which developed from a slight hiccup into last time loosing one bank completely. I had to drive it home across town with the car kangarooing as the cylinders dropped in and out. So this was enough for me and I had to get it sorted but of course at idle it was fine and only under load would it break down after driving 5 miles or so. Sort of heat related. Being a Euro model it does not come with the diagnostic set up of the US cars so I thought I would retrofit the system to aid finding the fault. This is a cheap and easy mod and very useful. My car is on test pipes so the cat temp warning modules are disconnected so I know its not those.

Button switches are still available from Ferrari. Part no. 145810.

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Your ECU loom will need the extra wiring which is fitted to the 2.7 Motronic. Approx 20cm in length with a blanked male AMP connector shown below.

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There is a connecting loom shown in the parts diagram but I had the bits so I made my own rather than wait a week. These go from the buttons to the ECU looms. AMP 3 pin. Half kit needed each side. You could just buy one button and make one loom and use it both sides. Some spade connectors and heat shrink.
Use pin slots 1 and 2 although there are three wires at the loom plug. Plug numbered.

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You need to fit two bulbs into the dash pod. 2 x 2 Watt capless. The empty bulb holders were in the very centre lower row of lights. This picture shows them with the ignition switched on but engine not started. They should go out when engine running.

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So now with the engine started I have a warning light randomly flashing on bank 1-4 so I suspect this is the problem side.

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I then do a fault code readout off both ECUs using the buttons and check lamps as described in the workshop manual starting page C 78 and only get code 4121 off each which is Cat temp modules which have been disconnected previously so expected. I then start thinking it may be an ECU issue as no other codes so I swap them over and the warning lamp now moves to the left to cyls 5-8 as shown below. Time to send it off for testing.
The results of that was a fault in the ECU probably caused by a voltage spike at some point. The engineer was happy to put the symptoms I described to him initially down to that fault. Cost for long testing and repair was 327 USD or £250. No Ferrari bill or probably £2500.
Anyway, fitting the diagnostics helped pinpoint the problem quickly so well worth it for me.
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Here is a short video on reading the codes. His codes are both Lambda sensor related. He dosnt say in the vid. There is a list in the WSM.

 

Sure. There is no obvious issue at the connectors but Ive cleaned them anyway. I have some 22a.