Almost no one talks about the method of troubleshooting a car. And this is correct, because it is useless to talk about it. This is the same as trying to paint a picture without a brush, paints and canvas, only in words. However, judging by the issues that sometimes flash on our automotive forums, the demand for this is great. You read, you are surprised and ask yourself: “Well, why does this person think that this so-called” troubleshooting technique “can be set out on paper?” Even so you can say: “The troubleshooting technique is like clouds in the sky. Now they are of one shape, and in five minutes they will take a different shape.” In other words: “There are no identical problems. As there are no identical methods for finding and eliminating any technical problem..
Sometimes they ask me: “What method did you use?” Then I fall into a stupor and do not find what to answer. Let us try to answer similar questions with this material using the example of troubleshooting on a 2012 Mitsubishi L200.
Mitsubishi L200 is a compact pickup truck manufactured by Mitsubishi Motors since 1978. The modern model (2006-) in a number of countries is sold under the name Mitsubishi Triton. Available in versions with a two-door double (Single Cab), two-door four-seater (Club Cab) and four-door five-seater (Double Cab) cab. Depending on the configuration, it can be equipped with air conditioning, an audio system, an automatic or manual gearbox, an Easy Select (part-time) all-wheel drive, or Super Select (on-demand full-time) all-wheel drive, an electronic rear differential lock, an exchange rate stability system Esp. wikipedia.org/wiki/Mitsubishi_L200
Options and rich electronic filling. But do not be scared and assume something serious: “all cars, in principle, are the same.” And the first thing that is done is car photo. From all sides. And to the question “Why?”, I will cite the words spoken at the “Second Conference” of Auto Repair Technology. Diagnostics of modern power units by “lecturer Sergey Evdokimov:
“- There was an expensive BMW car, we did it as it should, checked it, and how we started to give it to the client – that one was dissatisfied, they say, you broke the joystick. And its cost is from 100 to 150 thousand rubles. And what to do in this case? But you don’t have to do anything: … we’ve got used to it… carefully inspect it, describe all of its “Kotska”, take a photo, etc. when accepting a car for repair… So on this machine – we showed the client a photo, we provided the client a description of his car at acceptance (condition and identified problems) and what? He is so modest in stupid and said: – Sorry, something I messed up a bit … “. “Second Conference. Day One”
Probably, the majority of those present at the conference faced the following:
Second action – Definition of a code (codes) of malfunction
It is best to use a dealer scanner. Why: third-party scanners can interpret the DTC in their own way, starting from an error in determining the fault code and ending with an incorrect translation (if the scanner is translated into Russian). However, there are times when some object under study on a machine is best tested not by a dealer scanner, but by another (this is stated in the article “Hyundai Sonata. Radiator Fan” ).
“”. I’ll just say that Scanmatic-2 sometimes helps me out very well. Its coverage is not like that of a dealership, but, for example, it’s very, very convenient to diagnose the “SS4-II” distribution on Pajero4 on it. Even more convenient than through MUT3 “”.
More convenient, yes. But this does not mean at all that you need to throw MUT3 into the far corner and try to work only with Scanmatik. Car diagnostics is a flexible thing, it doesn’t give in to “solutions to the forehead”. “Dying is necessary, dying”.
I always remember that “electronics is the science of contacts,” and, for example, if the scanner was unable to contact the car, then I don’t get angry and do not kick the scanner with my feet: I remember that it does not hurt to check the status of the diagnostic connector, the presence of all pins and the state of the pins (it was found that some contacts were simply absent, or were recessed in the connector, or were oxidized, which made the connection impossible).
Well, in this case, the scanner detected an error on the rear left sensor of the ABS system: “C1020 – Deviations in the rear left wheel speed sensor circuit”.
“WHAT specifically will we repair !?”
The client told:
– He drove the car for repair, the diagnostician diagnosed a trouble code with a scanner and rushed to his computer with all his might. Something began to search. Found. Reads carefully. I look from behind, and he STUDIES the principle of operation of the malfunction that the scanner found. So what? And why do I need such a repair when the diagnostician does not know what he will repair?
In my opinion, the principles of operation of car systems, the features of repair should be kept in mind. Another thing is when a “plug”, when a dead end and you take a timeout to bring your brains in order. And to drive a car for repair and not know WHAT you will repair …
On the same machine, when the scanner detected a malfunction, my brains clicked and switched to the main one: “There are MRE type speed sensors here, which means there are features …”. What features? Much has been written about them, I will not repeat:
– “Electronic car security systems”
– “Ford Fusion”
– “Mitsubishi Lancer MRE”
– “Nissan Pathfinder 2007 MRE sensor, break in the harness ABS”
– “Mitsubishi Outlander (2008). MRE Speed Sensors”
When searching for any malfunction, the diagnostician should be similar to a hound that senses prey – in addition to the “upper instinct”, the “logic for finding and determining malfunctions” should work.
It’s hard to explain with words, I’d better quote Aleksey Nitochkin, an auto-diagnostician from the city of Elektrostal, how he looks for a malfunction and builds his logic:
Check: press the gas pedal and watch the readings.
– 2.5 volts constantly “hangs” on the sensor “A” and the signal does not change when you press the gas pedal.
– On the sensor “B” the signal is adequate, changes from 0 to 5 volts and vice versa, when you press the gas pedal and smoothly release it.
Conclusion: “Pay attention to the sensor” A “, put its performance in doubt and check, comparing with the manuals and readings of the sensor” B “.
· Remove the connector from the accelerator pedal position sensor
· The voltage on the sensor “B” has come clearly to zero
· The voltage on the sensor “A” remains “hanging” in the region of 2 volts
· “Sensor” A “receives a spurious (” left “) signal
· The reason may be a violation in the wiring harness (receipt of the “left” voltage from some other wire due to a violation of the integrity of the insulation)
· The cause may be a malfunction of the control unit
How to check the assumption that a malfunction is in the control unit (or not in the control unit):
· Disconnect the connector from the control unit
· We measure tension on a plait of wires (gauge “A”)
· Turn on the ignition, measure the voltage at the contact of the gas pedal
· We see that there is already a voltage of more than 3 volts with the ignition on
· Reconnect the control unit and see that the voltage has returned to a reading of 2.5 volts
· The reason is not in the control unit
· The reason is not in the accelerator pedal
Simply put, you need to “put together a bunch of thoughts” and clearly outline the circle of troubleshooting. Do not scatter.
This is said figuratively. But if such cars are often repaired, then the necessary scheme is always in the head. If not, it’s worth refreshing the memory, looking at the diagram: something may fall out of memory, and this, according to the law of meanness, will be most necessary. Usually I look or manuals on the topic, or Motordat, there for me there is the most necessary: schemes, pinouts and more. I do not put Motordat above all programs, I can only say that “it’s more convenient for me: you can easily and, most importantly, quickly find the right scheme”.
Interested in specifics. The desired sensor, “rear left,” is highlighted in red. S85 is a rear left ABS sensor with MRE type sensors. I study, I draw Special attention to the intermediate connectors F12 and C29:
Why did I say that “I pay special attention”: you see, such “intermediate connectors” are very moody. Especially after meeting with car services. The latter is important. And this is also said a lot in articles on the Legion Avtodata Internet portal:
– “His Majesty” The Human Factor ”
– “Renault Symbol. The Human Factor”
– “Human factor and car wiring”
These are just some of the articles that describe the ordeal of car repairmen that eliminated the poor quality work of colleagues. If you search, then there are more such articles.
Few people pay attention to these intermediate connectors, although they are one of the most vulnerable places in the car wiring: such connectors have each their own place, each factory has fixed each one in its place and it is not recommended to move them to another place or leave them loose after work . Simply put: “I worked with the intermediate connectors – return them to the mounting location set by the manufacturer, and most importantly, check the reliability of the connection of the contacts and the locks of the latches.” That the head then did not hurt.
The third thing I’m doing is, once again, as if by the way I’m looking for some conversation with a client and again I ask him “the history of the car.” I already asked this client, but he didn’t remember anything. But there is hope for the construction of human memory: when you ask again, his memory is already “running” with the first question, and he can remember. Or not be able to. Here it’s how lucky. But such questions often save a lot of time. I asked a second time. And he remembered: “Once upon a time they put additional equipment on the car … either the rear window heater, or the rear seat heater”
Very well. To compare “malfunction of the rear left speed sensor” and “did something in that place” is not difficult. And where do they lie and where are the main harnesses packed, I know. Previous specialists couldn’t put food on their “extra” other than next to or near the main harness.
Question: “- Where is the most” sore “place when laying harnesses?”. Probably where the greatest chance of moisture getting or seeping? Probably. Therefore, I open the threshold and look. Surprisingly, I immediately got into a malfunction:
This is an abnormal wiring (but it also comes across the same one), this is the connection of “dopa” – additional equipment. Wires and connections were laid in the doorway, but they weren’t done very accurately – they just laid, just without isolation, just “made and got money for the work.” And what will happen next was not interested.
And the chronology of the malfunction is as follows:
1. Route your wires and connector
2. Do not fasten the connector
3. During movement, the connector began to dangle, and gradually began to grind the wires of the main harness
4. And ground.
That is: “Everything would be fine if the connector were fixed, but not left to mop in the wind”.
And the last one. I wrote this not for professionals, but for those people who are just taking their first steps in auto diagnostics. When I wrote, I used additional material from articles on the Legion-Avtodata company’s Internet portal, where the words spoken by an auto-diagnostician from Sakhalin Oleg Suslin caught my eye. I want to repeat them again: “Diagnosis is not work, it is a way of life”.
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