M52TUB25 Cruise Control Retrofit Challenges

[gookah]

Right, I have done some more testing

Logged on to INPA with my M52TUB28 (manual gearbox)



so If you select the Engine screen:

then select your engine to get the following screen:

choose F5 to read status to get this screen:

then choose F1 digital values to get this screen:

Choose F1 again Digital Allgemain (not sure why this went to German)

this gives the following screen:

You will see the 3 circles for
Clutch switch
Brake light switch
Brake light test Switch

All 3 circles should be clear until you press a pedal

Press Clutch to operate clutch switch and put a black centre in the circle whilst pressed


When you press the brake pedal slowly, the brake light switch will go black, followed by a black circle in the brake light test switch
The first brake light switch circle also corresponds with the brake lights coming on, regardless of if the test switch has not been pressed far enough in.

 

[staggerwing17]

OK so I was apparently misreading the Peake R5 FCX3 scan/reset tool. I finally found instructions for this specific tool and here are the displayed codes when doing a Fault code (Fc) scan:

Display: 15, 92, 27​

What it means:

15 - this is not a fault code; rather, it refers to tables included in the manual. Once in the table, you can look up the number and see the description.
92 - EVAP capillary leak (0.5mm) detected
27 - Brake light switch (BLS)/brake light test plausibility​

I am hoping that I have now interpreted the codes accurately and that the 27 code indicating a brake light issue might be the culprit. Still waiting on new brake light switch.

About INPA - I have been looking for the VAG KKL K-LINE OBD2 USB Interface Cable with FTDI FT232RL Chip referred to in the Z3 Diagnostic Forum on bimmerforums.com (https://www.bimmerforums.com/forum/...tions-Experiences-Discussions-Experimentation). I know that the quality of these cables is important but I am having a tough time discerning good from bad. The best one I found is here:
https://www.obdinnovations.com/vag-kkl-k-line-obd2-usb-interface-cable-with-ftdi-ft232rl-chip/. It appears to be robust and has excellent reviews. Alas, it is out of stock with an unknown restock date. I see this on eBay (I prefer to buy USA if possible): https://www.ebay.com/itm/VAG409-VAG...280238?hash=item2cee0b51ae:g:jksAAOSwKQJdGz0V Does this look like a good cable for the INPA purposes? Please let me know and thank you!!

 

[NZ00Z3]

Yes code 27 is the usual one from the brake switch which trips up the CC

Yes that KKL cable looks OK.

You will also need the 20 pin round connector cable like this one https://www.ebay.com/itm/ASSEM-BMW-...256777&hash=item2ad23b0f65:g:H-EAAOSwtAhdTovX

 

[staggerwing17]

SIGH!! Well, replaced the brake switch today. No brake switch error now but alas still no cruise control . SO I will take it on a longer drive tomorrow (oh the burdens we must endure!) to make sure code 27 does not reappear.

VAG KKL FLTD FT232RL cable arrives tomorrow and I already have the 20 pin BMW to 16 pin OBD cable so it looks like INPA may be an option to not only confirm that switches all operate as they should but also that the FGR Interface Module is seeing CC stalk signals and talking to ECU. Or maybe I need to see if the ECU sees the FGR module at all.

At any rate I am thinking that the FGR module is probably no good. I talked to the seller on eBay and while his ad says 170 point inspection of the donor car, and all parts are functional, he admitted they did not test FGR module.

This is a frustrating but also very educational process. It is worth the time and effort!

 

[staggerwing17]

Took the car for a longer drive and checked codes after. Code 26 - clutch switch. Sigh.....

 

[staggerwing17]

Accomplished the following:

• Installed INPA - outstanding directions, cool software. Got a couple of errors in the final install screen but PC recognizes the car and most of the systems.
• Cleared codes with INPA.
• Viewed brake switch, clutch switch and FGR module in INPA:

• Brake switch is behaving somewhat properly according to INPA. The problem with the brake switch is that the first switch on depressing gas pedal activates after BARELY touching the pedal. Sometimes, when I release the pedal, the first switch will remain on. Sometimes not. If the switch remains on even with nothing touching the pedal, I can hook my foot behind the brake pedal and pull back on the pedal. The switch then indicates OFF in INPA:

• I will look at it some more - the stop for the released brake pedal seems a bit sloppy. Perhaps the return spring is weakened? Plus the red adjustment collar on the switch does not seem to be snug enough to remain in one place. Will look at that again as well.
• Any thoughts or recommendations here?

• The clutch switch, a 3 pole switch, just started causing a 26 error code.This one thoroughly confuses me. INPA shows that the switch is always ON (filled circle) regardless of the clutch pedal position. And yet, the car will not start with clutch pedal out. It will start with the clutch pedal in.
  • So obviously some part of the switch is working and perhaps some part is not?
  • Is this a simple 3 pole mechanical switch or is it a hall-effect switch?
  • I am seriously considering carefully disassembling the switch to see what's what.
  • How do I determine the chassis number to use in INPA?

• The cruise control FGR shows all the correct functions on the INPA screen. This means to me that the stalk is fine and that the FGR module is at least receiving the signals from the stalk. I don't know if the FGR module is doing anything on the outbound side.

• How would I confirm that FGR is signaling the ECU?
• How do I know that the ECU is receiving signals from FGR?

Any help on any parts of the above is appreciated! For those in the US, Happy Labor Day!!

 

[NZ00Z3]

Hi

Just back from a 2 day classic car rally, had a lot of fun with an assortment of great classic cars. 85 cars in total including 4 Z3's.

Well done in getting INPA set up, working and using it.

Brake switch
The plunger is self adjusting. That is, the plunger will push through a catch to get to the right length for your peddle travel the first time you push the brake peddle. You may need to push the plunger "in" one more "click" by hand.

Clutch Switch
This will be the fault that is stopping the CC. The 3 wired clutch switch is a hall effect switch. Its electronic and not normally a serviceable part. You can still have a go at servicing it, but I would recommend buying another one.

Remember the first lot of codes that you decoded correctly had both brake switch and clutch switch error codes. Having to replace both switches is rare, but looks to be correct in your case.

INPA Chassis Number
Not sure I understand the question. You select "E36" at the start menu for the Z3. Under Chassis is a list of modules, some your car will have others it will not have. A bit of trial and error and you will sort out the ones you have.

FGR
Your module is working correctly. The module converts the analogue signals from the switch/stalk into the digital bus protocol used by the car. When you test the FGR you are looking into the engine DME (ECU) and seeing the digital signals from the FGR change. So the FGR is all good.

Hope this is helpful

Regards

Murray

 

[staggerwing17]

Hi Murray!
I hope you enjoyed the car meet! And believe me, anytime you write back to my seemingly endless questions, your responses are extremely helpful.

Great news on the FGR module. I am hopeful that resolving these switch issues will get cruise control functional. I tend to get cramps when driving on the highway while trying to hold a consistent speed. SO the cruise will be a great help!

As for the INPA Chassis Number, I should have said INPA Body Number. It is the last item on the menu after selecting E36 using F2. There are a number of options and I am using the first one in the list. I will send you a screen print shortly as soon as the weather cools off a bit.

I will order a clutch switch - it was far easier to remove than the brake switch though after reading more it seems a mirror and needle nose pliers can be used to gently squeeze the side catches (with plunger and red collar pulled out as far as possible) to get the switch out unharmed. I will be an expert soon!!

Thanks again sir - will update this thread soon!!

 

[staggerwing17]

WAIT A MINUTE! I am looking at the clutch switch in my hand. And it just this moment occurred to me that the red collar around the plunger serves (possibly) no function other than to push the two mounting tines outward to lock the switch unit in place in its bracket. It has nothing to do with the plunger self-adjusting function?

If this is the case, how does one reset the switch to an unadjusted state so that remounting it results in the proper self-adjusting action?

Am I way off base here? Could be the 102 degree heat!!

 

[NZ00Z3]

Hi

You are correct in that the red collar is just for mounting the switch.

On the Brake Switch, the plunger can be pushed into the stop, then when you apply extra pressure the plunger clicks along a ratchet. You can also pull the plunger out along the ratchet. I over pressed "in" on a switch when changing one once and discovered the self adjusting feature. Try it out on your old brake switch. Then you can look at adjusting your new brake switch one more click. I have just looked at your photos in post #1 and realised that I may have put you wrong on the direction of adjustment. I may be a one click "out" on the plunger to make it longer so that the switch states change earlier and you don't need to push the peddle up with your foot.

I have not played with a clutch switch to see if it has the same self adjusting feature.

 

[staggerwing17]

Hello! So with all the help and the video below on YouTube, my brake light switch is now behaving perfectly! INPA such a big help. So waiting for a new clutch switch and am hoping this resolves my cruise control issue so I can button uo the driver's side underdash.

View: https://youtu.be/m13PvjsRsBk

 

[NZ00Z3]

Excellent work, one switch down, one to go.

 

[staggerwing17]

I am looking for the correct Chassis item in the INPA E36 sub-screen. I have been selecting the first item but want to make sure I am using the correct one. The Body sub-menu contains things I have and don't have as you described previously whereas the Chassis sub-menu has items but not sure which is right. I also don't know which transmission to select in the Transmission sub-menu.

Wow, I don't seem to know much! I know I have the right car and engine at least...

 

[staggerwing17]

Last question (for now), where should I post the following error screen had at the end of the INPA install? Should it be posted in the thread on bimmerforums where the instructions are? INPA seems fine and I might just try a reinstall but it would be helpful to understand the errors. Thanks!

 

[NZ00Z3]

You have the correct engine DME sorted, well done.

Transmission only relates to automatic transmissions. As you have a manual transmission, you will not need to used this section.

Chassis will relate to what's in your car, ASC or DSC for traction control. My guess is that you have ASC, so "ASC MK20/DSC E46" is the likely one for you. Its trial and error to get the correct one. Steering angle sensor only relates to a DSC car.

Body is trial and error to find the modules your car has.

Post the error message in the forum tread where you got INPA. The tread owner is very good at problem solving the install.

 

[staggerwing17]

Delete

 

[staggerwing17]

Received the new clutch switch today, installed and still no cruise control. Car will start only with pedal depressed. New switch behaves exactly as old one where regardless of the position of the plunger, the INPA circle for clutch input stays solid.

1. The issue with INPA showing a solid circle with either clutch switch is exactly the same thus not a likely point of failure
2. The FGR module tests fine in INPA which seems to indicate that the signals from the CC control stalk are making it through the FGR to the DME
3. The brake switch tests fine for both functions (brake lights and cruise control deactivation) plus other functions
4. The CC stalk tests fine
5. The starter interlock works fine
6. The problem I am facing is not (yet) a cruise control issue - it is a clutch switch issue only

I can only imagine that there might be an issue with the .35 BL/BR wire which, according to the Electrical Troubleshooting guide and the Bentley Manual wiring diagrams, runs from the clutch switch to the DME 42.1.

Pointless conjecture: since PART of the switch function works I can only assume the ground and power legs of the switch are OK but the signal may wire may not be and a default condition of "pedal depressed" as seen from the DME allows the engine to start? But then that would mean a fault in (both new and old) clutch switches?

I have been poring over electrical diagrams and also trying to learn more about hall-effect switches and how to test them but most of it is beyond my current skills. SO I am again at a bit of a loss as to how to proceed. I know for certain that I am not putting the driver's side underdash back together until this is resolved. SOoo:

1. Does anyone have any insight based on the above information?
2. Since the issue here is a clutch switch issue, should I start a separate thread for that and then wrap up this thread once the clutch switch issue is resolved and cruise control can be tested?

I am off to have a gin 'n' tonic. Maybe that will help!!

 

[staggerwing17]

So, after the gin 'n' tonic I had a thought. Murray I think you mentioned in one of your posts that my car, being on the cusp of change, "Some ECU's required cruise control enable coding." I think you were referring to 2 wire clutch switch systems but perhaps since the clutch switch works properly as an interlock, perhaps the ECU needs to be told to enable cruise? I am just out of ideas...

 

[NZ00Z3]

Sorry for the slow response, been off to a car show for the last two days. Was a lot of fun, great cars and people.

Let work through a couple of clutch switch issues first. I do not think that you need to code the DME for CC.

My 2.0 Z3 is similar to yours, in that its a M52TUBXX engine, manual, 3 wire clutch switch, manufactured in 4/99 and has had cruise control retrofitted. My car does not have the "clutch needs to be pushed" start function.

1) Are you still getting clutch switch error codes with the new switch? If so, then that indicates the new switch could be faulty.

2) If you work/operate the switch in your hand and plugged into the wiring, can you get the INPA black dot to go out? If so, this will indicate that your problem could be the adjustment of the switch or mounting bracket when installed. Does the clutch switch have a self adjustment feature like the brake switch?

3) Is the wire broken between the clutch switch and the DME? How good are you at using a multi-meter and finding the ends of the wire? Do a continuity check of the wire to make sure the clutch switch signal is getting through.

4) Test for a Voltage signal change at the clutch switch and DME from the clutch switch. The voltage could 5V or 12V to earth. Set the meter up then turn on the ignition and work the clutch switch to see if you get a change in signal. Try at the the clutch switch first to understand what signal there is.

Stick with this thread for the clutch problem as its all related to CC.

 

[staggerwing17]

Hi Murray! Glad to see that you survived another car show!

• My car does have the "depress clutch to start" function (it's a USA thing). It works properly.

• A 3 pin hall-effect clutch switch was in the car when I bought it. The car had no cruise control stalk, module, etc.(weird to have the 3 wire switch but no cruise - I know the car was manufactured in a period of change so maybe that is why).

• (Your Question 1) The new clutch switch DOES NOT throw error 26. The old one did.

• (Your Question 2) In INPA the Clutch Switch Input circle always remains full - no manner of jiggling, plunger positioning, plug jiggling, etc. causes the circle to turn clear. The clutch switch does not adjust - the plunger is a solid piece with NO serrations and thus no adjustment mechanism like we see in the brake switches. The round end of switch plunger, when installed, is about 1/2" away from the TOP of the pedal: thus the travel at the BOTTOM of the pedal is similar to what you observed in yours.

• (Your Question 3) SO now we come to challenging part. I too had though that the .35 brown/black wire that goes from the switch to the DME might be nicked or broken. But here is the rub - if the wire is broken, how is it that the "depress clutch to start" works properly? I assume that the DME is responsible for processing that function and thus the 12V signal wire must be properly connected and in one piece.

• (Your Question 4) We tested the clutch switch in situ - that is, attached to the plug. There are 0 volts on the signal wire when the plunger is fully extended (clutch pedal at rest) and 12 volts when the clutch is depressed. So the switch is functioning as it should.

If we assume that the switch is fine and the connection from the switch to the DME is fine, that leaves only the DME as an issue. The DME is somehow showing a permanently depressed clutch pedal through INPA. Thus my thought that some setting in the DME might need to be changed. And further, it seems likely to me that BMW would not have cruise control activated in the DME if it was, in fact, not equipping that "on the cusp" car with cruise control.

That leads to NCS Expert and NCS Dummy. I was able to read the DME modules with NCS Expert although the series of 2 digit hex codes delimited by commas means nothing (unless I could find a table that lists modules, and the potential values for each position of the data in those modules). NCS Dummy seemed to somewhat fit the bill, making language translations and offering checkbox activation/deactivation of options. I messed around with reading various modules, just to familiarize myself with the software. That is where I am now.

Next step I think is to better understand the modules, their features and the current settings. That is unless you find a glaring fault in the logical assumptions above. As always, Murray, I am all ears, and continuously grateful for your assistance!!