348 spider ABS problem

Problem with my ABS system, help appreciated.
Coincidentally after my recent state inspection the ABS light came on. Thinking it was just an incorrect signal I disconnected the battery for 5 minutes. Upon start up the light remains on. All brake functions appear to work fine. Have not attempted to activate the ABS system with a hard panic stop. Checked fluid level etc, all fine.
Removed the luggage liner and performed a system test per the workshop manual.
Code readings were light lit 4 seconds, 2 flashes, pause, 5 flashes, 6th light on continuous.
I believe this is error code 2.5
Failure code 2.5 is: Valve: Right front return
Type of failure is: Valve or connecting wire defective or Defect in control unit(power transistor)
Repair instructions: Check valve resistance and continuity or Also check wiring and connectors.
Pulled right front wheel, only connector is a blade type ground? Also a bolt fastened connector for the speed sensor?
Traced the brake line back to where it enters the master cylinder unit. There appears to be an assembly under the master cylinder with 3 distinct units in the casting. Is this the valve in question? Only connector I could locate close to this assembly was a large multi blade type connector that I removed and cleaned with Stabilant. The connector appeared very clean.
Please advise areas I could troubleshoot. I completed a major last year as well as rebuilt my gearbox but admit no knowledge of ABS systems, feel a bit lost. What can I check?
Winter here in MA so I have plenty of time to repair if I can. Thank you.

 

John,
I do not have the solution, but my 328 does the same thing. The light is just always on, but I do not have any codes. It has been checked, bled, inspected with no luck. I did overfill the resevoir once, and the light stayed out for almost a year. But it is back, and nothing seems to cure it.

I hope you find the solution, since I think it may apply to mine also.

My threads:
http://ferrarichat.com/forum/showthread.php?t=12614&highlight=mule+abs

My other thread is on the old site, but it does not appear to be accessable.

 

Mule, thank you. I read your prior post. I am not familiar with the 328 ABS system but on the 348 you can access the fault codes easily. Do you have a service manual? If you have the manual the brake section should have instructions detailing how to troubleshoot your problem.
On my 348 I accessed the electronic control assembly. There is an empty slot for a fuse. Installed a fuse, turn the key on and count the ABS light flashes to establish the code. My problem is I do not know how to proceed from there. I freely admit troubleshooting the ABS system is a mystery to me.

 

John,

You need a "breakout box" and a multimeter (see picture) to check the various wiring circuits - for example I can tell you the resistance for the right front return valve is between 3 - 5 Ohm, this is read with the diagnostic equipment connected, ignition on, car raised and the wheel turned by hand, but without the test equipment it is very hard to diagnose.

Should the valve be found to be defective, sadly it's part of the hydraulic unit and is not supplied seperately by Ferrari.
Image Unavailable, Please Login

 

While the break out box is very handy, you can open the back of the ECU plug and use very thin lockwire down the back of the wires too.

Have a wiggle around with connections, and remember that the light won't clear until you've driven the car fault free for a while... I think it's over 50km/h for a few minutes or something, don't have my notes to hand.

 

Phil,

Once the car has exceeded a speed of over 40 kph as long as no further faults are identified, the memory is erased.

 

Malcolm, Phil, thank you for the information. Reading the workshop manual I was afraid the answer was going to require special equipment. I will start by cleaning and resetting all connections with Stabilant. I will then try the resistance check per Phil’s instructions using a multi-meter. Hopefully the problem is only a connection issue and not a faulty valve.
I believe the unit is manufactured by ATE. Perhaps I can source a valve from them if required.
My other problem is testing. Winter here north of Bostson. May not be able to test and reset the light until Spring!
Thank you again, John.

 

John,

If it turns out to be a fault with the return valve, you may be able to send the complete body to ATE who MAY change just the faulty part instead of replacing the complete assembley - keep us posted.