[srini1785]

Originally Posted by a4anurag

[b]....While browsing the parts applicability list, there was something that caught BHPian interc00led’s eyes, the same part was available in the ‘Aftermarket Parts’ section of the listing with the real image matching the part we were looking for:

Part Name: Reverse Light Switch
Part Number: TD-1114
Price: ₹266.00

First up, thanks for sharing this trouble shooting experience. Your persistence finally paid off.

Its not surprising that both neutral and reverse switches look and probably are the same. They are , IIRC, normal mechanical switches which sense the position of the gears through mechanical contact. The only thing that might differ is the length of the spring loaded plunger at the front which has a direct bearing on when the contacts close. So it might not be interchangeable in spite of having the same threads on the body.

For all the high tech glory that companies claim that they are, its finally a simple mechanical contact. Could anyone shed light on why CAN bus is not used any more?. It could have at least given some kind of diagnosis over the bus.

[audioholic]

Originally Posted by srini1785

. Could anyone shed light on why CAN bus is not used any more?. It could have at least given some kind of diagnosis over the bus.

What do you mean by CAN BUS not being used any more? CAN is a form of network for communication between ECUs as well as a diagnostic interface. It is very well being used in these cars while more complex cars use better networks such as flexray, ethernet and a combination of different networks as per the need. A few posts earlier we have discussed about the issue of diagnosing over this network.

[AttyBhai]

Well explained. Thanks.

[srini1785]

Originally Posted by audioholic

What do you mean by CAN BUS not being used any more? CAN is a form of network for communication between ECUs as well as a diagnostic interface.

Yes but not at the sensor level. Signals such as gear position can be easily sensed through an optical or even a contact type encoders which can be directly wired to a CAN or IO Link bus. But these are still wired in discrete mode and no intelligence is built into them. IO Link/CAN bus or for that matter any bus enabled sensors can pass on diagnostics over the bus which would have made life easy for diagnostics of this sort. Whats more, non contact sensors have better and longer life.

[audioholic]

Originally Posted by srini1785

Yes but not at the sensor level. Signals such as gear position can be easily sensed through an optical or even a contact type encoders which can be directly wired to a CAN or IO Link bus. But these are still wired in discrete mode and no intelligence is built into them. IO Link/CAN bus or for that matter any bus enabled sensors can pass on diagnostics over the bus which would have made life easy for diagnostics of this sort. Whats more, non contact sensors have better and longer life.

I agree on the non contact sensor part. But thats a different topic compared to having the sensor over CAN. You can still have a non contact sensor sending binary signal which is more long lasting and cheaper to make. Adding CAN functionality will just increase cost without giving any other benefit especially when it has to only transmit two states. Even for that sake the use of a simpler network like LIN wont give any benefit. The diagnostic capability what you say is already present in the current system without making the sensor CAN compatible. CAN will benefit only if the sensor was supposed to be more intelligent and give higher amount of data. For example, steering controls of the mass market cars are based on analogue resistance based signal transmission. This will work when we have relatively lesser amount of signals to transmit, like say volume controls, etc. But as we move to the higher priced cars, it is a CAN based system when you start involving more and more functions into the steering like cruise control(safety relevant), paddle shift etc. Hence, it is not a one solution for all scenario and it is decided by the complexity of the system. These days, engines of premium cars have ditched CAN and have moved to Flexray, due to additional burden of signals as well as higher fault tolerance. But that comes at a cost, one of the reason why it has not yet made its way into cheaper mass market cars.

[srini1785]

Few points before we move on.

Originally Posted by audioholic

But that comes at a cost, one of the reason why it has not yet made its way into cheaper mass market cars.

At 11L, Creta is not a cheep mass market car

Originally Posted by audioholic

The diagnostic capability what you say is already present in the current system without making the sensor CAN compatible.

I doubt it. If it were the case then the contact fault would have showed in the in the diagnostic software. If it weren't for the presence of mind of the OP, this would have triggered a visit to the ASC and who knows further delays with no guarantee of a correct diagnosis. Had it been a fully liked bus system through flexray or LIN, this failure would have got all red LED's glowing. In the present system, or at least in Creta the CAN bus seems only to be a communication bus between different ECU's.

Originally Posted by audioholic

CAN will benefit only if the sensor was supposed to be more intelligent and give higher amount of data. For example, steering controls of the mass market cars are based on analogue resistance based signal transmission.

Agreed. Critical systems are still wired the conventional way. Not only in cars even in industrial environments. Only monitoring signals are wired through bus systems. Closed loop controls like steering control is rarely done through bus systems and is done more reliably through analog systems with fail critical MTBF components.

[audioholic]

Originally Posted by srini1785

At 11L, Creta is not a cheep mass market car

I doubt it. If it were the case then the contact fault would have showed in the in the diagnostic software.

If I speak about electronic sophistication in 'Expensive' cars, I am referring to the BMWs and Mercs and the like. In the global context, our A, B, C segments are still equivalent to mass market though for us Indians owning a C segment or above is like owning a premium car. These cars are relatively far simpler in electronics though they show a list of features. A car like Creta can have perhaps 10-15 electronic controllers at max, while if you go through a Mercedes, they have anything from 40-100 control units with a mega vehicle network consisting of ethernet, Flexray, CAN and LIN along with their network gateways. I hope you now understand what I mean by a sophisticated system and an expensive car

Coming to the point of the diagnostic software, if you go through my earlier posts in this thread, I have already explained how the neutral switch has fault detection already implemented not only in Hyundai, but even Maruti with the sensor still being an analogue sensor without a data BUS. Here is the link to the post https://www.team-bhp.com/forum/techn...ml#post4868714 (Hyundai Creta 1.6L CRDi - Violent shaking of the car (Neutral Switch Issue))

So, the issue can be detected in the current setup is what I am trying to convey. If there are further open points, we can surely discuss if you feel there is still a better way to this issue. My standpoint is that by using a switch that works on CAN, the diagnostic happens at the switch and the error is transmitted to ECM. In the current setup, the diagnostic happens at the ECM and error is generated there. Thats the only difference.

[mh09ad5578]

Incredible trouble shooting @a4anurag and @interc00led and great insights into the tech @audioholic. The biggest problem with visiting the ASC at least for non technical guys is they generally replace parts totally unrelated to the problem and just inflate the bill. I've come across incidents where injectors were replaced where only replacement of fuel and air filters would have sufficed. I doubt the ASC guys could have pulled such tricks on anurag but I'd be really suspicious of what they say. Thanks for sharing. Like always a great post.

[catchdoon]

Super stoked to see yet again a typical Anurag who just refuses to give up.
There's just so much to learn from you mate.
I'm in awe at the fact how Hyundai failed to showcase in the ECM.

Having said that, absolutely brilliant approach & kudos to keeping strong head until resolution.