Santa Fe (speedometer not working)
The story is super-instructive. Because no need to relax!
The beginning is this: the mistress of this car turned to our auto repair shop with a problem: when driving, the speedometer shows zero kilometers per hour. Interesting. I ask: nothing lights up on the dashboard, no light? I mean the CHECK banner.
– No, nothing like that, everything is fine.
OK well. But well-known scenarios scroll in my head: some craftsmen either pasted the light bulb with adhesive tape or built a circuit when the CHECK light comes on and goes out as it should. Or the bulb just went out.
A scanner to help, as they say. For such non-core I have Bars 3. We connect, we look, really, there are no expected errors. Again ok and the sentence:
– And let’s go with you and the scanner. Let’s see what will show in motion.
Here comes the first dead end in the head: the scanner displays the real speed, and the speedometer both stood and stands at zero. Logically, this begs: the problem is either in the wiring, or in the speedometer itself, since the speed sensor is working – the scanner shows speed. Well, the control unit is also working, it turns out …
With kandachka with such a problem can not figure it out. It is necessary to leave the car and understand more closely.
I open the computer, find this car, look. From the speed sensor, the signal goes to the control unit, then to the diagnostics block and to the instrument panel. Since the sensor, its circuit and control unit are serviceable, I decide to see what comes to the diagnostic block.
Test drive. I connect the LED indicator to see the potential change on the block, on the desired pin. There is nothing. The only conclusion is: “An open between the control unit and the diagnostic block”.
I decide to check the speedometer. I take my pulse generator (I already wrote about it and showed its work in previous articles, a useful device), I plug it in and the speedometer comes to life.
The conclusion is: the speedometer is serviceable, the speed sensor is serviceable, the wiring is serviceable, which means that there is no communication between the control unit and the diagnostic block. Understanding comes that “the matter is clear, that the matter is dark” …
To troubleshoot I am preparing FF-310 (I also wrote about this necessary device, who doesn’t have it – purchase it, it’s useful). A thorough search. Carefully. The thing is dark! I checked it twice. I could not resist, and for the third time walked along the chain. Conclusion: the circuit from the speed sensor to the diagnostic block is working!
Here in this place I was swept by a complete impasse! He ran into such a normal concrete wall and froze in the question … how so? From the block to the speedometer, the speed signal is perceived by the control unit, but the signal from the speed sensor is not perceived on the speedometer! How can it be?
I decide to connect the signal emulator not to the block, but to the speed sensor connector and see what the scanner and speedometer will display. Here my eyes begin to expand in bewilderment: the signal from the sensor to the speedometer arrives, but the control unit does not see this signal. Although, when the car is in motion – everything is exactly the opposite! No, it’s too early in the morgue, on the lift. I rotate the wheels in turn, look at the scanner. And only at that moment I understand that the comrades Koreans used duplicate chains. Two chains. Independent from each other: from the speed sensor and from the ABS sensor.
From the ABS sensor, the signal comes to the engine control unit
The speed sensor provides information only to the speedometer and to the diagnostic block
That is, two independent sensors and two independent circuits.
What about the circuit? The diagram shows that the control unit receives the signal only from the speed sensor on the box.
He started to understand, his eyes were in a heap, he sat, tortured his computer and the Internet for a long time … and this turned out to be:
It all depends on the vehicle equipment and for which market it is intended
There are many modifications on this car for the American and Canadian markets: with automatic transmission, with “mechanics”, with ABS system, with one engine and with another engine, etc. … and for each modification its own algorithm for constructing signals and tracking information on speed. On one, the signal is removed from the speed sensor, then the signal goes to the speedometer and to the control unit. On another configuration, the speed signal is monitored in two circuits. Etc.
According to the photo:
20 – engine compartment
24 – here in these bowels of wire-tubes speed sensor is hiding …
26 – with grief, I crawl in half to the speed sensor …
30 – dashboard, it is clear that the speedometer gives information about the speed – 100 km-h, and the car stands still, the signal is emulated by a generator
31 – the appearance of the pulse generator, it is also a simulator of signals from the speed sensor, it is also used to test ignition coils and other things … a universal tool
32 – photo of the monitor at the time of displaying the sheet date, the bottom line shows zero km-hour, while in photo 30 the speed is emulated at 100 km-hour
37 – the appearance of the speed sensor, when viewed from the side on this gear, it can be seen that it has semicircular wear
Moral: a separate gear was purchased for the sensor, everything was replaced and everything began to work successfully
Kudryavtsev Mikhail Evgenievich
Car service “VTS”
Suzdal St. 9
You can call during business hours:
Without keyword This car came with a problem: “The speedometer is not working.” To the question “how exactly doesn’t it work?”, The client replied that…
Without keyword The malfunction is interesting: “the cooling fan is constantly spinning.” A person turns on the ignition – does not spin, but as soon as…
Hyundai Terracan – TOD System (ATT)
Without keyword The ATT (Active Torque Transfer) or TOD (Torque-on-Demand) system is classified as the Full Time 4 WD system. This is an all-wheel drive…
Without keyword Hyundai Santa Fe (about retrograde in the practice of car repair, – 🙂 (from Latin retrogradus – going backward), an adversary of…