Testbench setup?

   #161  

_Val

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Need some help with CAN signal pairing between different generations...

Current bench test setup:
- 1K0 gateway (1K0907530C) from VW MK5. Obviously it has Convenience and Diagnostic CAN buses. Other ones doesn't matter now.
- Parking aid ECU from Audi A6 C5. It has K2 line for diagnostics and Convenience CAN as shown in Elsa diagrams. A6 C5 facelift instrument cluster acts as "gateway" just like on newer cars. But because of instrument cluster is so bulky I'd like to wake up parking aid ECU with some real gateway which is many times smaller in size.

I can connect gateway with VCDS, but parkings doesn't want to open a connection to K2.
Parking aid ECU is ok, was tested in real A6 C5 car.
Tried with parkings checked in installation list and unchecked. Didn't help either way.
Wiring rechecked multiple times.

Voltages on convenience CAN-H = (0.25V ... 0.32V changing) and CAN-L = (4.64V ... 4.75V changing) with parking ECU connected (don't have a scope for now, but analogue multimeter shows it).
Voltages on convenience CAN-H = (2.53V) and CAN-L = (2.46V) with everything disconnected (except gateway itself).

Isn't it possible? :D
 
   #162  

Uwe

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Isn't it possible? :D
I am skeptical that it is possible. C5 Audi uses almost certainly used older CAN protocols (TP1.6) vs. Mk5 (TP2.0).

-Uwe-
 
   #163  

1975 Kombi

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Great thread and thanks for all the help. I've been able to log onto the RNS510 and alter the settings. Awesome input from everyone. Thanks again.
 
   #164  

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Great thread guys. I have been tinkering with an Audi Q7 4M MIB2 (Nvidia - not newer qualcomm) bench setup. I too have struggled with the "virtual" T15 signal and the issue with this setup is you either need to have a CAN sniffer that can generate (TX) CAN messages (which I have) or have an appropriate J393 (BCM2) to generate the T15 message to wake-up the MIB2 which then wakes up the screen. The issue with the Q7 J393 is two fold. (1) Unless you get the CAN gateway from the car that the J393 was taken from, you get Component Protection activated. When CP is activated on this module it pretty much immobilisers the car - no T15 message. In a real car, you won't be able to start it. (2) All Q7s have Kessy (here in Oz anyway).. Hence, you need the key from the car and the antennas setup etc... very painful.

With the J393 disconnected, and can get the screen to wake-up but then it goes off again using CAN messages I have captured from my car. I am wondering whether I am missing some other CAN messages or whether. I have the wiring incorrect. With the MIB2 high, you need a CAN connected screen and controller or the MIB2 will definitely reboot.

Speaking with someone else, they have successfully got this same bench setup working with the Audi MIB2 stuff connected to a VW MQB CAN Gateway (5Q0907530M) which is also connected to the J393 from the same car (5Q0937086Q). I would obviously like to just send the appropriate CAN messages to get this working on the bench without J393 CP activated.

For those interested, the Terminal Management characteristics on the Q7 4M are:

Scenario:
1. Pressing the start / stop button E408 when term. 15 is "off"
2. The signal of the pressed button E408 is transmitted to the central control unit for convenience system J393 via discrete lines.
3. The key test is performed by J393 (correct key in interior /immobiliser) → steps 4, 5 and 6 are performed in parallel with key test.
4. Release message from J393 to electrical steering column lock J764 → J764 released.
5. J393 activates term. S and term. 15 (allowing short time delay between term. S and term. 15).
6. Irrespective of the engine starting conditions, J393 generates the term. 50 signal (discrete line and CAN signal) for approx.200ms in order to the fill the start request memory in the ECU → When term. 15 is turned on, J623 decides whether the conditions for engine starting have been met (based on brake / clutch / driving position) and switches the term. 50 relay.

If the start/stop button is pressed while the ignition is on, J393 decides on the basis of a bus signal from J623 whether an engine start request has been generated or not. If an engine start request has been generated, term. 50 (hardware and CAN signals) is output for approx. 200 ms. If no engine start request is generated, term. 15 is switched off if the switch-off conditions have been met.

The selector lever position is evaluated by J623 (CAN message and hardware signal starter enable, P/N signal).

Finally, does anyone know what effects CP has on a CAN gateway? As I mentioned before, on a Q7 4M, CP on the J393 pretty much immobilisers the car. CP on the instrument cluster removes DIS info, with MIB2, you get limited audio from the speakers.
 
   #165  

DV52

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spyder: G'day cobber!! I had pretty much the same problem on my MQB platform test-bench (but for different reasons). My first test-bench incarnation had a "forced" T15 solution whereby I used a single-pole, single-through hand switch to create the T15 bus voltage from the test-bench power supply- the problem that I created though was some weird incompatibility with some BCM (called J519 in the WD) functions depending on the position of the simulated ignition switch on my test bench. In frustration, I eventually wired an old single contact telephone relay that I found in my junk box to the BCM pin that controlled the Terminal 15 voltage supply relay (it's called J329 on the MQB WD) like this:



Works like a charm on my test bench (but I only have 1 x BCM)

I also have multiple CP errors on the test bench because I sourced the CAN Gateway, the Instrument module and the BCM from different cars. Since my test bench is mainly used for educational purpose (mine and a phalanx of local forum members), CP errors aren't an issue - albeit you are correct that CP on the hex17 module does impact the FIS (but not for Output tests -03)

Don

PS: isn't it comforting that DIN 72552 designation for switched voltage is half that of the designation for fixed "hard" voltage? I assume that if there was such a thing as a switched-earth that it would have the designation T15.5!!;)
 
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   #166  

jf1

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Great thread guys. I have been tinkering with an Audi Q7 4M MIB2 (Nvidia - not newer qualcomm) bench setup. I too have struggled with the "virtual" T15 signal and the issue with this setup is you either need to have a CAN sniffer that can generate (TX) CAN messages (which I have) or have an appropriate J393 (BCM2) to generate the T15 message to wake-up the MIB2 which then wakes up the screen. The issue with the Q7 J393 is two fold. (1) Unless you get the CAN gateway from the car that the J393 was taken from, you get Component Protection activated. When CP is activated on this module it pretty much immobilisers the car - no T15 message. In a real car, you won't be able to start it. (2) All Q7s have Kessy (here in Oz anyway).. Hence, you need the key from the car and the antennas setup etc... very painful.

With the J393 disconnected, and can get the screen to wake-up but then it goes off again using CAN messages I have captured from my car. I am wondering whether I am missing some other CAN messages or whether. I have the wiring incorrect. With the MIB2 high, you need a CAN connected screen and controller or the MIB2 will definitely reboot.

Speaking with someone else, they have successfully got this same bench setup working with the Audi MIB2 stuff connected to a VW MQB CAN Gateway (5Q0907530M) which is also connected to the J393 from the same car (5Q0937086Q). I would obviously like to just send the appropriate CAN messages to get this working on the bench without J393 CP activated.
I finished putting together a bench setup over the weekend and was able to power it up by pressing "MENU" on E380. No T15 message was required on Infotainment CAN - nothing is connected to those pins for the time being. MIB CAN is connected as normal to J794/E380.

J685 - 8W1919605
J794 - 8W5035880D
E380 - 8W0919614T

I do see a couple differences with my setup:
- J794 is a MHI2Q unit (Qualcomm)
- CP is not active on J794

Haven't had a chance to capture live CAN data from my B9 so leaving it all disconnected from power for now. Hoping I can write some code to emulate the missing heartbeat from J533 to prevent J794 from eventually timing out and triggering CP.
 
   #167  

DjDvr

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Hey, bringing this up a bit as I have also started playing around with a test bench.
I am running a PQ35 A3 BCM + Can Gateway specifically for cluster wakeup but I hit a snag with 2 things:

1. What do you guys use as a coil to read the key ?
2. Since the 2005+ clusters need 2 wires for fuel how do you guys get rid of the low fuel warning ? I can remove all bulb warnings with a simple led setup but cannot get rid of the low fuel warning error.

Any help would be appreciated.

Cheers,
 
   #168  

DV52

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Dj: Hi and great to read that you are cultivating an interest in a test-bench. They certainly are an excellent device for furthering one's knowledge. However, I agree that they can be frustrating and cantankerous (especially in the early stages of development).

So- with the caveat that my test-bench has an MQB base (rather than your 8P platform) - I have managed to simulate the petrol-tank function on my test-bench (but ironically for quite the opposite reason - I actually wanted to generate the low-fuel warning error albeit under controlled conditions). See the graduated dial that I've attached to the instrument panel in the upper part of my picture below:



Of course, my solution for the petrol tank simulation won't work in your test-bench. However, whilst I don't have access to the WD for the 8P - I have been able to develop the following "2 x wire" set-up for the fuel gauge from a mk5 Golf (which has a similar build platform)



In many ways, the mk5/8P set-up appears to be very similar to my MQB arrangement. As you can see, and as a very general statement - the sender part is analogous to a simple variable resistor. So you should be able to use one of these with the wiper pin (the center tag on the picture below) connected to the gauge pin on the module. Note: I'm not sure of the "wetting" current for these senders - so it's probably wise not to use a mini version of these variable resistors.



BUT - the crucial bit is selecting the resistance value. I'm not sure what this might be for your hex17 module - but for my test-bench, I settled on 200 ohms. This value doesn't give me full gauge sweep - but it does allow me to hover comfortably at the ON/OFF point for the low-fuel warning error with my graduated scale set at around 50%

Don
 
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   #169  

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Dj: Hi and great to read that you are cultivating an interest in a test-bench. They certainly are an excellent device for furthering one's knowledge. However, I agree that they can be frustrating and cantankerous (especially in the early stages of development).

So- with the caveat that my test-bench has an MQB base (rather than your 8P platform) - I have managed to simulate the petrol-tank function on my test-bench (but ironically for quite the opposite reason - I actually wanted to generate the low-fuel warning error albeit under controlled conditions). See the graduated dial that I've attached to the instrument panel in the upper part of my picture below:



Of course, my solution for the petrol tank simulation won't work in your test-bench. However, whilst I don't have access to the WD for the 8P - I have been able to develop the following "2 x wire" set-up for the fuel gauge from a mk5 Golf (which has a similar build platform)



In many ways, the mk5/8P set-up appears to be very similar to my MQB arrangement. As you can see, and as a very general statement - the sender part is analogous to a simple variable resistor. So you should be able to use one of these with the wiper pin (the center tag on the picture below) connected to earth, Note: I'm not sure of the "wetting" current for these senders - so it's probably wise not to use a mini version of these variable resistors.



BUT - the crucial bit is selecting the resistance value. I'm not sure what this might be for your hex17 module - but for my test-bench, I settled on 200 ohms. This value doesn't give me full gauge sweep - but it does allow me to hover comfortably at the ON/OFF point for the low-fuel warning error with my graduated scale set at around 50%

Don

Thank you for the quick reply. Is the MQB also reliant on a 2 wire setup ? So 2 wires giving a resistance value that is then grounded ?
I can certainly give that a try, I have 2 resistors for now that I can try with and earth those what I don't know is if it expects resistance on both wires to the dash or only on 1 :D what switch did you use for example ?

Also what did you use for the coil to read the key ? Just a dismaneteled contact switch?

Cheers,
 
   #170  

DV52

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Thank you for the quick reply. Is the MQB also reliant on a 2 wire setup ? So 2 wires giving a resistance value that is then grounded ?
For MQB, all 3 x wires in the sender are wire back to the hex17 module - and I assume the sender is earthed via an internal return path.


I can certainly give that a try, I have 2 resistors for now that I can try with and earth those what I don't know is if it expects resistance on both wires to the dash or only on 1 :D what switch did you use for example ?
I've changed my mk5 WD!
On a closer inspection of my WD for the mk5, it seems that the wiper for the variable resistor should connect to the gauge pin on the hex17 module. Then connect one of the outer pins on the variable resistor to earth and the other pin on the variable resistor to the non-gauge pin on the module.

Again - I'm just guessing, but extrapolating my amateur understanding of the WD - I assume that the module needs to always see a fixed value resistance between the non-gauge pin and earth. I suspect that this is how the wetting current on the sender is generated and this is how a fault in the sender is detected (I think there must be a fixed supply voltage for the sender on the non-gauge pin).



Again guessing - I assume that the measurement part of the function is ostensibly the tapped-off voltage through the wiper at the gauge pin (I think)

I didn't use any "switch" - none is needed, just a single variable resistor

Also what did you use for the coil to read the key ? Just a dismantled contact switch?
OK - this bit gets more complex and this is why I didn't address this matter in my first reply. At least for MQB, there was no actual need to read the key data on my test-bench to waken-up the other modules. What was required was to replicate the physical impact of the key operation as it affected the electrics. So yes, "just a dismantled contact switch - but wired into the hex44 module - which apparently generates the module wake-up message on the CAN bus. See the components on the lower part of my test-bench picture (note: I've "externalize" the C-switch in the ignition key because there is no actual physical key to close the "C" switch on key insertion- you might want to do the same)
 
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   #171  

owdi

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Guys, quick question, for the MK5 Golf 1K platform, I know its possible to make a quick/dirty bench loom to communicate via OBD to a MK5 Golf cluster using power, ground, CAN High / CAN L etc, is it possible to add an ECU to this setup without adding a CAN Gateway? Can I just add the CAN H/L from the ECU to the cluster/OBD CAN H/L and have the cluster communicate with the ECU?
 
   #172  

Jack@European_Parts

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Indeed it is possible but sometimes you may not get the response you seek unless a proper pull up termination is implemented or a filter for traffic.

Always best to incorporate a gateway.
 
   #173  

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@DV52

I am now in your debt kind sir :). I am now happy sitting between 19 - 27 L which is more than perfect to get rid of the error message :). Now to the next part of figuring out how to trick the post 2006 clusters to work on single wire setup :P so we don't need to swap fuel senders to make the gauge work , but this is a totally different topic. I will send over a case of beer or your choice of beverage if you PM me an adresss. Cheers
 
   #174  

DV52

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@DV52

I am now in your debt kind sir :). I am now happy sitting between 19 - 27 L which is more than perfect to get rid of the error message :). Now to the next part of figuring out how to trick the post 2006 clusters to work on single wire setup :P so we don't need to swap fuel senders to make the gauge work , but this is a totally different topic. I will send over a case of beer or your choice of beverage if you PM me an adresss. Cheers
DjDvr: Arrhhhh........... I always like it when I have someone in my debt!!! ;) However, my price for advice that actually helps someone (it happens very rarely in my experience) is much, much higher than a "case of beer". :)

Instead, and as a quid-pro-quo - I simply need your undying gratitude and I ask that you share any findings from your test-bench adventures on this forum. Both of these forms of payment are far more valuable to me than a "slab" (Aussie term for a case of beer).

Don
 
   #175  

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DjDvr: Arrhhhh........... I always like it when I have someone in my debt!!! ;) However, my price for advice that actually helps someone (it happens very rarely in my experience) is much, much higher than a "case of beer". :)

Instead, and as a quid-pro-quo - I simply need your undying gratitude and I ask that you share any findings from your test-bench adventures on this forum. Both of these forms of payment are far more valuable to me than a "slab" (Aussie term for a case of beer).

Don
The eternal gratitude is automatically gained for someone who helps form the kindness of his heart so you have that , the slab was an extra thank you I would send as I was trying to understand the da** logic of the fuel thing for a while now :D. A nice suitecase will follow for my test bench and I will detail that in great detail once I finish. For now it seems a 100 ohm variable resitance gives me for the A3 clusters 19 to 27 L playroom and a 500 ohm one only gives me FULL . 55 L no matter where I turn it , so will give it a try with a 50 ohm one as well .

Next step for me will be understanding the difference between 2003 to ~2006 vag cars with 1 fuel sender wire and the 2006+ one with 2 sender wires and looking for a way to trick that without having to mount a new fuel sender. The "old" ones are like this:

https://imgur.com/gFzCWU5


where the 2006+ ones have the extra wire on position 4 as well and new cluster complain without the 4 wire so that is my next project for now but at least I have a good starting point now :P
 
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   #176  

DV52

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The eternal gratitude is automatically gained for someone who helps form the kindness of his heart so you have that , the slab was an extra thank you I would send as I was trying to understand the da** logic of the fuel thing for a while now :D. A nice suitecase will follow for my test bench and I will detail that in great detail once I finish. For now it seems a 100 ohm variable resitance gives me for the A3 clusters 19 to 27 L playroom and a 500 ohm one only gives me FULL . 55 L no matter where I turn it , so will give it a try with a 50 ohm one as well .

Next step for me will be understanding the difference between 2003 to ~2006 vag cars with 1 fuel sender wire and the 2006+ one with 2 sender wires and looking for a way to trick that without having to mount a new fuel sender. The "old" ones are like this:

https://imgur.com/gFzCWU5


where the 2006+ ones have the extra wire on position 4 as well and new cluster complain without the 4 wire so that is my next project for now but at least I have a good starting point now :P
DjDvr: Probably wise to set aside any more hagiography!! ;)

Again, I'm not familiar with these early model A3s, but your diagram above does make sense from an electrical perspective; it looks like it's a simple 2-wire transducer. Forgive me if you already know this stuff, but as we have discussed, the fuel level sensor is ostensibly a device whose electrical resistance changes with the volume of fuel in the tank. And, as we both have observed through experimentation, the sensor can be easily mimicked by the type of "potentiometer" that is often used in electronic devices.

There are 2 x ways of applying potentiometer type devices to an electrical circuit:it can can be configured as a simple "variable resistor", or it can be incorporated into the circuit design as a "potential divider"

Hopefully a better way of understanding these two applications is via the diagram below:



As you can see, when a potentiometer is used as a "variable resistor" , only 2 x pins are needed. In this mode, the measuring device (be it either the physical analogue meter, or more likely a "shunt" for the analogue meter) is wired in series with the transducer and what is actually being measured is the electrical current flowing through the variable resistor. As an interesting aside, circuits that have transducers wired in this way need to accommodate zero ohms in the sensor - so they always have some form of current limiting function in-circuit.

The other way of using a potentiometer is as a "potential divider". These devices need 3 x pins and rather than measuring electrical current, as the name implies, these circuits instead measure electrical voltage (i.e. electrical potential).

As the wiper on the potentiometer moves, the comparative resistances of R1 and R2 changes: the meter responds to the voltage variation across one of these resistors. A characteristic of potential divider circuits is that they need what's called a "wetting current" to produce the tap-off voltage that the measuring device monitors. Generally, this current is produced by a very stable voltage supply that is connected across the two ends of the potentiometer - that's why the third pin is needed in potential divider circuits (it's connected to the +ve side of the "reference voltage" supply)!

I suspect (hope) that this explains the difference in the 2 x wire and 3 x wire fuel level sensors in the 2003 to ~2006 vag cars

Don
 
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   #177  

DjDvr

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Totally does explain it and also kind of ends my quest of trying to find a software solution for switching between the 2 mods as I am know almost 100% sure that will not be possible due to the difference and also no way other than changing the whole sending unit when mounting a facelift cluster on the 2 wire era cars. The fuel level sender is not detachable so will play around in the test bench and see if I can find another way as from 3 to 2 wire you could just close pin 2 and 3 and get a 2 wire setup but the other way around is see no way of doing it as the sender does not have the 3rd pin. I know the fuel pump + sender swaps in no problem and just need to run the 3rd wire from pin 2 to have working fuel gauge. Thank you again DV52
 
   #178  

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Hello everyone!
I`m trying to get connected with a RNS300 on the bench via gateway like in the picture below. Trouble is that i`m not able to establish connection with the radio or navi, only with gateway. Is there anything else what i must add in this schematic? Any termination resistors? Anyhow if i measure resistance on infotainment bus on the car shows me no resistance between lines. If I mount gateway and radio in the car it works. so on the bench it must work asewll.
P.S. Pin 16 on the radio is connected to Vcc aswell.

Thank you!


 
   #179  

Uwe

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If I mount gateway and radio in the car it works. so on the bench it must work asewll.
P.S. Pin 16 on the radio is connected to Vcc aswell.
Does the radio power up on the bench? If not, it may be looking for a CAN message from another module, like a "virtual Terminal 15".

-Uwe-
 
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