2002 no Speedometer and no Power Steering

Ozvtr wrote: ↑Mon May 01, 2023 2:46 am Pin 2 of the black 10 pin connector in the BSM goes to pin G2 of the 48 pin maroon connector of the engine ECU. I found a better wiring diagram and the engine ECU connector is maroon not black. Sorry If that caused confusion.
It shouldn't go back into the passenger compartment!

So once again, the signal path should go from pin3 of the pick up sensor on the gearbox to pin G2 of the maroon connector of the engine ECU.
Inside the BSM there should be continuity between pin 2 of the 10 pin black connector and pin 14 of the 16 pin black connector.
engine 016.jpg
Continuity from pin 3 of the speed sensor to pin 14.
engine 019.jpg
engine 017.jpg
continuity from pin 2 to pin G2.
engine 015.jpg

The "Maroon" connector on the engine ECU is the middle one. If you look on the "ears" of the engine ECU's electrical connector, you will see no paint (black), brownish (maroon) and grey paint.
If you get continuity between pin3 of the speed sensor and pin G2 of the engine ECU then the problem is NOT the wiring. It could be the engine ECU but
1) the ECU is usually very reliable.
2) changing it is an absolute pain! This is the last thing you want to change.
I am beginning to get suspicious of your new speed sensor. 2 failures at exactly the same time??? The speed sensor and something else??

Hello Ozvtr
Once again, thank you for your help and time on this.
I have now tested all the wires and I can confirm that I have continuity on the yellow wire between pin2 of the black 10 pin connector in the BSM and pin G2 of the 48 pin maroon connector of the engine ECU. So this should confirm that the wiring is good from the speed sensor all the way to the ECU.
As you mentioned on your last reply about the speed sensor I went ahead and ordered and fitted a new one but this made no difference.
Do you have anymore ideas for me to try?

The Speedo and power steering don't really bother me much as I can drive the car. This is the first car I had with power steering so heavy steering don't affect me much.
What does bother me is the car stalling on junction (I have to give a slight momentary kick on the accelerator before stopping the car so it does not stall) and now I have realised that the fuel gauge doesn't really measure fuel once it gets below half tank... This wouldn't bother me otherwise but without Speedo I also have no mileage to calculate how much fuel I have left so lately my tank is always pretty much full every time.

If you have anymore ideas I am all ears.
I know it's an old car and I have been told several times this car belongs in the scrap... but mechanically this car is in really great shape and I don't see the point of scraping it if it still drives.

The engine ECU can use speed info in the calculations for managing the engine. Did the engine stalling start with the other symptoms?

I am stumped as to why the speed is not registering!
You need to figure out a way to see if there are pulses at G2 of the engine ECU plug (while the wheels are turning).
You could remove the speed sensor (but still connected electrically) and probe pin G2 of the connector to ground. If you move a magnet or piece of iron across the face of the sensor you should get a reaction on the meter. Does the sensor show +12V on pin 1 with the ignition on? The sensor needs to be powered (for this test).

The sensor picks up very small changes in magnetic flux as the differential ring gear passes by. Then amplifies them into a square wave (I guess 5V or 12V but I'm not sure). If you wave a magnet or piece of iron across the face you should get pulses on G2.

Ozvtr wrote: ↑Thu May 25, 2023 8:41 am The engine ECU can use speed info in the calculations for managing the engine. Did the engine stalling start with the other symptoms?

I am stumped as to why the speed is not registering!
You need to figure out a way to see if there are pulses at G2 of the engine ECU plug (while the wheels are turning).
You could remove the speed sensor (but still connected electrically) and probe pin G2 of the connector to ground. If you move a magnet or piece of iron across the face of the sensor you should get a reaction on the meter. Does the sensor show +12V on pin 1 with the ignition on? The sensor needs to be powered (for this test).

The sensor picks up very small changes in magnetic flux as the differential ring gear passes by. Then amplifies them into a square wave (I guess 5V or 12V but I'm not sure). If you wave a magnet or piece of iron across the face you should get pulses on G2.

Hello Ozvtr and thank you again for your help, time and patience

The engine stalling started at the same time. Basically once i noticed i had no speedo or ePAS i pressed the clutch to stop in the nearest safe place and the engine just stalled. Once you turn the Key it will start again and maintain idle. it just stalls if you go coasting down a hill in gear and then press the clutch. once this happens you can see the RPM coming down and engine stalls.

I have tested the pulses and confirmed i get 12V (bit its a negative that reaches the pin) at the ECU pin G2.
Tested in 2 ways - first by removing the Speed sensor (and spilling a bit of gearbox oil all over my arm) and then i tested it by puting the car on a ramp and just allowing it to slowly roll down a bit and i could see the multimeter changing from 12v and them back to 0v as the car rolled (come to think of it should have done this to start with and avoid the "lovely" gearbox oil smell all over me)

I took a picture at the speed sensor and multimeter connected :
I was always under the assumption that the signals reaching the ECU would be positives but from the my wireing on the picture you can see that the signal that reaches the ECU is a negative... is this right and supposed to be like that? in confused.

Thank you

You are more than welcome. I just hope that we can resolve this for you with as little pain as possible.

The engine ECU is definitely using the speed information to calculate it's management strategy and it's not correcting when the engine slows down. So the good news is that there isn't a second problem.
I am at work ATM and cant see the pic (it says the site cant be reached). I might edit this when I get home, if I can see the pic at home.
EDIT; one of the site elves (or gremlins) fixed picture link.
So are you saying that the pulses start at +12V and go down to 0v then up to +12V and so on? If that's the case then that's Ok. The engine ECU is just looking for an "edge" that is either going positive or negative. So whether it "starts" at 0V or +12V is not relevant, so long as there are pulses.
That's not good. That tells me the engine ECU is faulty. It is not reading the pulses from the speed sensor.
If you can confirm that the pulses are getting to the engine ECU but it's not getting any further, then you can only conclude that it's the ECU at fault.

This is the second time that I have seen an engine ECU fail in a similar way to this, and I am beginning to have my faith in the ECU's infallibility questioned!

P.S. It's quite common these days to run power (+12V) to a device then switch the negative side of the device to ground, to get current flow. Meaning if you probe the device you will find the +12V going to it but it seems to lack a ground (because that's the switched side). This is just a quick over view of how I think the speed sensor works. And why you get 12V out when it's not doing anything.

That was great information. thank you for your help once again.
I will now try to find a replacment ECU for my car and hopefully the next time i come back here is with the good news that my car is now working as intended without my foot working as "idle management" (its becoming such an habit now that i find myself kicking the accelerator even when im drivig company cars)

Regarding the ECU replacement... does that mean i will need to aquire a "new" ECU with BSI and a set of new keys or is it relatively straight forward to just get a compatible ECU ?

Thank you

Single_clone wrote: ↑Sun Jun 11, 2023 10:37 pm Regarding the ECU replacement... does that mean i will need to aquire a "new" ECU with BSI and a set of new keys or is it relatively straight forward to just get a compatible ECU ?

Thank you

You need the complete set of keys, Engine ECU and BSI to get a running engine.

You may also need to configure the BSI with Lexia to get the different modules to communicate if there is any mismatch between donor and recipient.

The mileage of the Odomoter will raise to the highest of the two (donor or recipient BSI).

Good evening everyone.
It seems that luck is not on my side when it comes to find a replacement ECU, BSI and Key for my car as I can't seem to find anything online.
The only thing I found was for a different model engine and the seller wanted £200 for it. That is probably the value of the car so...no.

With that said I have a different idea to fix (or bodge) this car.
From a diagonal read on the way EPAS work, it seems that the signal is coming from the ECU in a 0v -5v line... So... In my head I am thinking that if I find the right wires, I can just inject 5v and that will put the power steering at 100% power.
If this works, I can easily write a few Arduino code lines to read my speed sensor and turn that into a 5v pwm that will control the power assistance in relation to speed.

So my question now is... Will this work?
And if yes, anyone has the pinout of the EPAS connectors so I don't go in all cowboy and swap the polarity on some line?

This might be diverting a bit from the topic now but considering the car is now 21 years old (I wish I was this age again) , I think I will just run it until it dies. The idle and stalling I can now manage with with very little effort so ... I think this will be it.

Have a great day

Um...no.
The EPAS derives the speed information from the CAN BUS and changes the torque assist accordingly. The engine ECU (in this case) puts the speed info onto the CAN BUS. All of the information on the CAN BUS consists of a series of coded pulses.

I don't know your skill, but I might be possible to use the arduino to inject a CAN signal onto the BUS, but that's way beyond me. You would need to learn the CAN BUS protocols.

Have you tried looking on the 'net for ECU repairs or exchange units?

Hello everyone.
I bring good news... the car is fixed.
No parts have been replaced (apart from the previous mentioned speed sensor) and it was all done with Diagbox 9.68.
Purchased (too many) weeks ago from AliExpress and it arrived last friday. After a few hours playing around with Virtual machines, software installations and such i finally connected the car to the laptop and had some fun playing around with the many options available with Diagbox.. you got to love playng with actuator and watch live data of your car being displayed on a laptop.
After scanning for faults i had a couple related to speedo (obviously expected) and a few that were injectors related,
After erasing the existing faults, then running a few tests with actuators on BSI and ECU, then reading faults again, everything was tested and passed on the scantool.
This morning i started the car and went to open the driveway gate (as i do every day) and the engine revs climbed more that usual at first second and the idle was more stable so it was clear that something was different but i didnt "connect the dots" until the glorious moment i sat in the car, shifted in reverse and grab the steering wheel only to be presented with a lovely and light power steering. After that i quickly noticed that the speedo was working correctly and everything else is now working as it should.

Once again, THANK YOU VERY MUCH for all your time and patience in helping me trying to diagnose the issue.
If by any chance the problem comes back (hopefully not) i will leave a new message here.

Hope you have a ggreat week.

Thanks for the update

Well done in fixing the car by changing the faulty sensor and clearing the fault codes

You don't need 9.68 to connect to a 2002 but it's good to know that there late versions do still connect to the early cars.