Did I Make The Wrong Call? Part II
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Date: 2020-08-05
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Comments and reviews: 10
Fred
Very interesting problem. I can provide a bit of explanation as to why the system was ''working'' even though there was a defect.
I will make an analogy with a guitar pick-up. When the magnet passes by, the magnetic flux lines that comes with it will induce a voltage in the coil of the sensor. Exactly like the metal strings of a guitar disturbing the magnetic flux of the pick-up.
In order to read the voltage from these disturbances, the ABS has a high impedance input. I will go out on a limb and guess it's around 10K ohms. which is fairly popular for voltage reading inputs. Because the impedance is very high, it doesn't need to draw big current from the coil, therefore, voltage drops within the wire, which could be interpreted as a series resistance, will be irrelevant. More over, the voltage generated from the coil will be the same at every parrallel branch of the circuit. Normally, the only branch would be the input. However, as you demonstrated with your testing, you had a 1MegOhm ++ resistance in parrallel to the input impedance. So, in the end, every single pulse sent from the coil coul be read with no problem by the ABS system because the voltage was true.
However, the problem arose when the car was stopped and there was no voltage generated from the coil. You see, resistances in parallel will make the total resistance of a circuit drop. Assuming I'm right with my 10Kohms input impedance theory (or any other value for that matter, the input impedance, in parrallel with the resistance created by the green schmoo WITH the impedance of the coil itself, will make the resistance fall below the expected impedance and the ABS module will either interpret this as a true voltage through current leak, or a shorted input. whatever the case though, it senses something is wrong with the input impedance.
I hope this explanation helps anyone who was wondering why it worked, but actually didn't.
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Very interesting problem. I can provide a bit of explanation as to why the system was ''working'' even though there was a defect.
I will make an analogy with a guitar pick-up. When the magnet passes by, the magnetic flux lines that comes with it will induce a voltage in the coil of the sensor. Exactly like the metal strings of a guitar disturbing the magnetic flux of the pick-up.
In order to read the voltage from these disturbances, the ABS has a high impedance input. I will go out on a limb and guess it's around 10K ohms. which is fairly popular for voltage reading inputs. Because the impedance is very high, it doesn't need to draw big current from the coil, therefore, voltage drops within the wire, which could be interpreted as a series resistance, will be irrelevant. More over, the voltage generated from the coil will be the same at every parrallel branch of the circuit. Normally, the only branch would be the input. However, as you demonstrated with your testing, you had a 1MegOhm ++ resistance in parrallel to the input impedance. So, in the end, every single pulse sent from the coil coul be read with no problem by the ABS system because the voltage was true.
However, the problem arose when the car was stopped and there was no voltage generated from the coil. You see, resistances in parallel will make the total resistance of a circuit drop. Assuming I'm right with my 10Kohms input impedance theory (or any other value for that matter, the input impedance, in parrallel with the resistance created by the green schmoo WITH the impedance of the coil itself, will make the resistance fall below the expected impedance and the ABS module will either interpret this as a true voltage through current leak, or a shorted input. whatever the case though, it senses something is wrong with the input impedance.
I hope this explanation helps anyone who was wondering why it worked, but actually didn't.
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Cody
And all I did was search, c0210 Scion and the first web match that came up was from 2006 and the second was 2008 both referring to rain/snowmelt and road ice getting passed a rubber seal. Internet is your friend my, um friend. As is service bulletins. Im almost 4 minutes into this video and Im pretty sure thats going to be the issue.
As mechanics were all go go go as time is money and we want happy customers. I work on RVs and its a pain in the backside finding diagrams where the body builders tie into the chassis wiring.
This was by far not your fault it came back, as everything was working fine. Cant fix something not broken. But with the process of elimination and reoccurring problems it makes it easier. Our shop only charges one scan fee and its with a cheap 120 scanner. (The other mechanic an myself want a good scanner and access to all wiring diagrams) but weve been taught by old timers and know the process of Elimination.
Your videos are great, always reminds me to keep it simple. Dont take customer complaints and symptoms to heart. Start with what you know. Hope when I finish this video Im right else everything I wrote was just being wrong. LMAO
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And all I did was search, c0210 Scion and the first web match that came up was from 2006 and the second was 2008 both referring to rain/snowmelt and road ice getting passed a rubber seal. Internet is your friend my, um friend. As is service bulletins. Im almost 4 minutes into this video and Im pretty sure thats going to be the issue.
As mechanics were all go go go as time is money and we want happy customers. I work on RVs and its a pain in the backside finding diagrams where the body builders tie into the chassis wiring.
This was by far not your fault it came back, as everything was working fine. Cant fix something not broken. But with the process of elimination and reoccurring problems it makes it easier. Our shop only charges one scan fee and its with a cheap 120 scanner. (The other mechanic an myself want a good scanner and access to all wiring diagrams) but weve been taught by old timers and know the process of Elimination.
Your videos are great, always reminds me to keep it simple. Dont take customer complaints and symptoms to heart. Start with what you know. Hope when I finish this video Im right else everything I wrote was just being wrong. LMAO
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John
That Autel is an beautiful thing, I can see why you frequently go for it.
Does it have an option to turn offauto ranging or set time/voltage divisions manually?
Was just wondering if right wheel signal had a different voltage signal, but tool auto adjusted voltage division to give you two signal graphs that looked the same during the first drive?
Anyways thanks for the video!
reply
That Autel is an beautiful thing, I can see why you frequently go for it.
Does it have an option to turn offauto ranging or set time/voltage divisions manually?
Was just wondering if right wheel signal had a different voltage signal, but tool auto adjusted voltage division to give you two signal graphs that looked the same during the first drive?
Anyways thanks for the video!
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Neil
Another great video. Surely worth grabbing a handful of fuses while at the junk yard, good for when you go through a few just fault finding? When I was at the scrap yard I used to grab a few extras, bulbs, fuses, relays etc.
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Another great video. Surely worth grabbing a handful of fuses while at the junk yard, good for when you go through a few just fault finding? When I was at the scrap yard I used to grab a few extras, bulbs, fuses, relays etc.
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Tanase
When you have this type of problems i think it's easier to switch the sensors between them, no matter if it's abs, lambda, or any-other two identical thingymegigie. it saves a lot of time from my point of view.
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When you have this type of problems i think it's easier to switch the sensors between them, no matter if it's abs, lambda, or any-other two identical thingymegigie. it saves a lot of time from my point of view.
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robert
That's what a call termination to find the problem and to fix the problem, thumbs up. Scotty would never have found the problem. I really don't understand why you are not number 1 in the ratings.
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That's what a call termination to find the problem and to fix the problem, thumbs up. Scotty would never have found the problem. I really don't understand why you are not number 1 in the ratings.
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Joshua
Can't thank you enough for taking the time to walk us through every step of this diagnostics and repair process. You're the only one, that I've found, who does this. Incredibly helpful.
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Can't thank you enough for taking the time to walk us through every step of this diagnostics and repair process. You're the only one, that I've found, who does this. Incredibly helpful.
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Matt
You know I was thinking, if it was touching the sensor wouldn't read the correct speed unless it reads from another sensor? But that doesn't make sense still.
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You know I was thinking, if it was touching the sensor wouldn't read the correct speed unless it reads from another sensor? But that doesn't make sense still.
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BR549
That big satellite antenna you referenced is for the C band, 3. 7 Ghz to 4. 2 Ghz. Now you can impress people with your communications knowledge.
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That big satellite antenna you referenced is for the C band, 3. 7 Ghz to 4. 2 Ghz. Now you can impress people with your communications knowledge.
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Jesse
Awesome but you shouldn't drive customers cars without a selt belt on. For your safety. Again thanks have a great day!
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Awesome but you shouldn't drive customers cars without a selt belt on. For your safety. Again thanks have a great day!
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