I am in the middle of trying to track down an abs/pdas failure.So i removed the 55 pin connector and went about trying to get readings for the pins i could think of that would be comprimised.
Here is th readings i got with car running and connector unplugged using multimter.so can someone take a look and see if anything stands out

For voltage pins :

pin 1 voltage terminal 15 got 13.4 volts
pin 11 voltage terminal 30 got 13.4 volts
pin 15 power supply (+) accleration sensors got 2.8volts
pin 20 power supply (+) valve and motor relays on hydraulic assem got 4.2volts
pin 27 D+ got 13.8 volts

For ground pins i have :

pin 9 ground acceleration sensors found no ground at pin
pin 52 ground went to ground

Now correct me if i am wrong but should the voltage at acceleration sensor power supply pin 15 not be 5 volts to feed the accelerometers? and if so what could cause loss of voltage?

Also should pin 9 ground for acceleration sensors not rest at ground when car running or could it be cause the connector is disconnected?



I also removed my wheel speed sensors and cleaned them up! the back ones were real dirty and didn't have the extra wire attached to screw with ring terminal like the front sensors had which i assume are the shielded grounds.

 

Paul, I have a C4 ABS schematic if that would help - but I'll bet you do also.

Yew have gumption, I'll give you that - and I honestly wish I could be a help.

 

Hi could you direct me to that ABS schematic if still available?

Best Regards
Glenn

 

Glen, C4 or C2?

 

its a 1991 C4

thanks
G

 

Glen, I have the 2 row C2 handy; the 3 row C4 pinout is in my Bentley book. When I get a chance, I'll scan it.

PM me with your email addy and I'll get it to you...a minor contribution of, say, $25K to Claudia's build fund would be nice also.

 

The rear sensors should have the shielded ground, I chased my ABS problem and it turned out to be the wiring from the sensor block that goes from the wheel into the frunk (in front) , I replaced the rears (not so bad) but the front right went into the frunk and it looked like the gas tank had to come out, so I spliced the wires and everything is Ok, I tested each sensor and they all read .99 @ 200 ohms then used Adrians book and read them from the ABS connector...thats how I found that the wires were broken, they looked intact from outside (cable covering was a bit brittle but not broken)
BUT should you use the meter on the plug to the ABS brain Adrians book has a typo, it says that you test the front left wiring at pins 4 and 5 but 5 is not used, it is in fact pins 4 & 6

 

Hey here is my ABS unit. Let me know where i can send to Claudia's build fund?
I took my ABS out and cleaned it all up, checked the diodes and resealed it

and thanks in advance for the schematic

Glenn

 

haaaa Claudia is your car?

 

Yessir she is...currently at Rothsport growing a set of *****, but she's still my sweetie.

 

glenn@glennrossstudios.com

thx

 

KaiB,

Can you send the C4 ABS Schematic if you still have a copy?

Thanks,

Joe