Questions on wiring on OBD2 S52 engine bay

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PlusOne,

Thanks for the input, that looks like a good call.

I spent time on the manuals this weekend detailing the X20 & X6031 pin outs on both the 318ti and the 323i.

Along with this issue, I am hoping that with the right connections, the 318ti ASC maybe could be made to function.

RealOEM has a different front cabin harness listed for the 323ti but I have not found an electrical troubleshooting manual for that model to confirm what the differences in the harnesses are.

Do you recall if you just cut and soldered or if you used a tool to remove and replace the sockets/pins in the connectors?

If I am going to try to make the connections the ABS/ASC module is looking for, I will need to add the "missing" wires or splice in the 318ti X20 connector since it looks like the CAN bus signals use pins 1 & 2 that are missing from the M52 harness.

Thanks

[PlusOne]

I removed the pin and transferred it to the other connector. If i recall it was fairly easy. There is a plastic retaining/locking ring on the face of the connector. You twist this slightly ccw to unlock the pins. You can then pull them out of the housing. search for x20 pin removal and you should get some hits on how this is done.

[PlusOne]

Check out this link
http://www.r3vlimited.com/board/showthread.php?t=154876

[Trusted-1]

Originally Posted by wodcutr

Hi, I saw that you did an obd2 swap into your ti and I have a few questions for you about the wiring.

I am putting an s52 from a 97 into my Cali top 97 ti. Both obd2. What wire changes do I need to do to allow everything to function properly? I was hoping to keep the asc and not have any cel on in the dash. Any help would be much appreciated. Thanks!

Dan

Dan,

I am still trying to see if the ASC can be made to work without having to swap entire chassis harnesses.

It seems like the signals are there for the ASC but I have not tried any of the connections yet to see if it will work.

The only other connection I think is needed is to get power to the chassis side of pin 8 on the X20 connector for the EVAP valve.

I have not gotten around to doing this and still have a CEL with an EVAP error because I don't think the valve has power.

I may get to it this weekend but my smog is not due until next year so other priorities have been ahead of this.

I will attach the info I have gathered so far and post to this thread when I have results.

Connecting the CAN bus from the M52 DME to the M44 type ABS/Slip module is unlikely to damage either from what I can tell but anything is possible.

Warning: I have not made these connections or confirmed operation so I do not yet know the results. Use at your own discretion/risk.

Steve

[wodcutr]

So you only have the x20 connection made from the engine harness and the only code you get from the dme is the evap valve? You made no wire changes?

[wodcutr]

Update: motor is in and running great. Had to shim my custom built e30 3.15 LSD down about 5/16" to allow for the 6 bolt M3 flange to clear the top of the rear subframe, but other than that everything went in well. Got a custom exhaust built and installed this weekend so now I can actually drive it without scaring the neighbors!

The car drives awesome and was well worth all the effort. Back end gets loose easily even with 225 slicks. This thing is a drifting monster! As expected the ASC light is on so I will have to pull the bulb in the cluster. I cleared all the CEL codes but keep getting a p0500 code that says it is the speed sensor.

I pulled all the wheels and tested each wheel speed sensor and they all ohmed out to be good. My abs light is on too! I'm pretty sure something other than a wheel sensor is wrong as the abs light is on at startup and would go out until I start moving if it was. I put an e36 speed sensor in the e30 diff and my speedometer is working great. When I hook up my obd2 live reader though I am not getting any speed in the dash command app so I am wondering if I need to connect some other wire somewhere to enable this and fix the speed sensor issue and also fix the abs.

Any thoughts on the matter would be greatly appreciated.

[John Firestone]

Originally Posted by wodcutr

... I cleared all the CEL codes but keep getting a p0500 code that says it is the speed sensor....

I think that is the right rear wheel speed output by the ABS/ASC unit. What year is the engine+DME?

[wodcutr]

Engine is an s52 from a 97 manual M3 sedan. Car is a 97 Cali top ti that was an auto. I shimmed my rear sensors up using a 5/8" washer to allow for the larger abs rings on the e30 axles. They are now about 1/8" away from the tone rings and both sensors tested good when ohming them out.

[Trusted-1]

I did not read the entire post but if the ASC throttle body actuator is not connected either the ABS or ASC (or both?) light illuminates.

It has been a month or two since I worked on it but I recall having to connect The ASC throttle body actuator even though it does not work.

I am still hoping to get the ASC working on our ti at some point but not if it involves swapping in the entire front harness from a Coupe or Sedan...

Hope this helps

[Trusted-1]

Originally Posted by wodcutr

So you only have the x20 connection made from the engine harness and the only code you get from the dme is the evap valve? You made no wire changes?

wodcutr, Sorry I missed this question but yes, no changes and it started and ran.

I got the EVAP CEL figured out using the info above and thought I had the connections right to make the stage 1 auxiliary fan work but when I tested it by shorting each side of the dual temp sensor to ground, still had no stage 1 function (stage 2 worked from the start, same circuit path)

I'll figure the stage 1 fan out at some point but it is low on the list for now.

[wodcutr]

Pull pin 8 of your x20 and pin 3 of the x20 and tie them together for the normal speed to function on the aux fan. Pin 8 for the x20 is replaced by pin 9 from the smaller 12 pin connector for the evap valve to function.

I did connect the ASC actuator and still no luck. Reading the diagrams it looks as if pin 9 of the x20 is the ABS wire that the DME is looking for. Both the ti and m3 used the same pin for this so it should be good as nothing was changed. I am wondering if the can high and low is causing the issue as nothing is connected to them through the x20 pins 1&2 that the ABS is looking for input from and the m3 DME is not supplying.

[Trusted-1]

I was thinking making the missing CAN bus connections might make the ASC work but have not tried it yet.

I laced back X20 3 & 8 to under the fuse box and connected them but it did not work for me. Relay did not even click. I did not check the relay so maybe it is just the low speed relay or fuse F16 are bad.

[wodcutr]

My low speed worked when tested at the radiator temp switch but I have not verified it when pushing the ac on as I'm not charged up yet. What year is your car? Is your ABS working? Does the ABS light come on when you start the car and turn off after the bulb check? You obviously are not getting a p0500 code. I wonder if I need to have a BMW tech hook my car up to a computer and tell me what's wrong. I hate throwing money at those guys!

[Trusted-1]

There are only two codes I have right now. A slow O2 sensor but I am sure it just needs a new sensor and the exhaust flap error (which does not throw a CEL) it shows up when reading with Carsoft BMW software.

I still have an old school reader on a a MacBook with Parallels that runs a Windows XP virtual machine but it reads the extended BMW codes. I tried Carsoft on Windows 7 but it won't run.

If you check online for Carsoft, I think it works with a bunch of $15 readers I have seen on fleabay.

Kind of a hassle unless you have an old XP machine around but maybe more productive in the long run to have around.

Steve

[wodcutr]

I am thinking the problem is because my car used to be an automatic. The trans has a speed sensor in it and since it is no longer there the wiring is not sending the signal to the DME. I think that regular manual cars have the speed sensor input from the RR abs sensor and I am trying to figure out how to get that signal to the proper place.

Any ideas?