Questions tagged [diagnostics]

Use this tag for generic questions related to tools, techniques and methodologies for diagnosing problems. Do not use this tag for case-specific problems, the "troubleshooting" tag is better suited for that.

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1answer
30 views

Is there a non-USB-OBD2 adapter made for reprogramming (CAN/ISOTP)?

I'm working on an ECU reprogramming and coding app (iOS, Android, etc.) for a client who is part of the automotive tuning scene. I have been trying out dozens of OBD2 adapters, but most of them fall ...
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21 views

Won't go when out in gear

I have a 1500 Suzuki intruder that I changed oil oil filter and gear lube on Plus changed plugs now when I put it in first it dies why
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2answers
77 views

What things cannot be tested(except by elimination) when trying to diagnose a sluggish engine?

As far as I'm aware there are certain things that cannot really be diagnosed if you have a sluggish engine and so you can only find them by elimination. As an example if you test a car due to ...
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1answer
128 views

How difficult is it to collect obd commands ?Will it be different for different brands?

OBD is something very interesting I found these days.Thanks to this repo https://github.com/pires/obd-java-api & wikipedia which provides the basic information of PIDs.But there is a lot of ...
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1answer
106 views

Safe rounding of CCA during battery load testing

How do you determine the safe amp load of a battery tester? I am looking at testing a battery on a 2012 Mazda 3 sport which has a Mazda factory battery 75D23L (52). The service manual states in the ...
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1answer
27 views

Can an OBD2 tester do a battery load test?

This Autophix device device was suggested by a review as the best of five battery testers. The text implied that includes testing cranking amps. But it can only connect to the computer—has no way to ...
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4answers
2k views

Simple fool proof way to identify Bank1 and Bank2 side

Is there a simple and fool proof way to locate which "side" of the engine Bank1 or Bank2 is on, with reference to OBDII data? For example, you read ODBII live data and find that Bank2 Sensor2 (...
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1answer
333 views

Fuel rail pressure - how long should it hold?

My factory service manual states fuel pressure should be 50 psi with the engine running at idle. This is a six cylinder 2008 Subaru 3.0R engine with a return-less fuel line to the injectors. ...
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1answer
383 views

Chevy 3.5 engine tick

I have a 08 Chevrolet Impala with a 3.5 with 70k miles. There is a tick that corresponds to engine speed. It's a pronounced tick but I highly doubt its piston slap or rod knock. It seemed like an ...
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0answers
15 views

4cy automatic 1997 Toyota Camry. The windows won’t roll down and car will not start. The alarm keeps going off

I have a 1997 Toyota Camry. After installing a new battery the cars alarm is going off and will not start it just cranks. I can’t even roll the windows down or unlock the doors. Any help
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1answer
263 views

Not receiving multi line response ELM 327

I am sending the following commands to my Hyundai i20 2012 model (OBDLink SX Bluetooth device): AT Z AT H1 AT L1 AT S1 AT AL AT SP6 AT SH 7D1 18 00 FF 00 The response I am getting is 7D9 10 0B 58 03 ...
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1answer
479 views

Help !!! 2007 Honda Accord 2.2 diesel not starting intermittently

my Honda Accord has developed an issue where by sometimes it fails to start when the key is turned, it will turn over but not start, the green key light stays Stays flashing on the dash, does this ...
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1answer
36 views

how to check car for impending failures? [closed]

My kia Sorento 2007 failed on me multiple times. Each time disabling the car and putting the driver in danger harmonic balancer alternator radiator and water pump in each of those failures, I had ...
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35 views

Can faulty relays cause fluctuating run performance or will they either be on, off or intermittent?

Car is experiencing reduced performance as well as stalling. Assuming these are caused by the same issue is it fair to say it cannot be a relay. Reason is because, as far as I’m aware, a main relay ...
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1answer
84 views

How to diagnose if battery is faulty or alternator is faulty

Little Background: I own 2016 Mazda CX-5, battery that came with car was not holding the charge for long, so after some research on which battery to replace it with, I decided to replace it with ...
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91 views

Peugeot 207, Head gasket blown?

4 vti coolant has a brownish color and its oily to the touch. I did an oil change about two weeks ago, I'm wondering if it could be connected, the coolant level didn't really budge. I remember the ...
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5answers
7k views

Suzuki sv650s will not start, no lights, no fuel pump, nothing

My sv650s will not start at all. I put the key in the ignition and turn it on and none of my accessory lights come on and the fuel pump doesn't engage. It's done this before and I fixed it originally ...
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4answers
73k views

How to test for defective glow plugs?

On a diesel engine, how can I know which glow plugs are defective, and can I change these only?
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1answer
39 views

Sad, whiny, stressed out, constipated noise when AC is on. Is it dangerous?

Another hot one today... I noticed in my Ford 5.4 v8 1998 van, when my AC is in the process of workin (like in the time between when it clicks on and clicks off), if I'm driving at certain speeds (...
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0answers
68 views

Which DLC terminals are known as DLC bias terminals (or should it be DLC Bus terminals)

This is related to Test 5 of this question: OBD II Scanner refuses to communicate with the vehicle! Funny that I should be asking this but then .....it happens Unfortunately, I cannot remember. I'd ...
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1answer
14k views

2011 Jeep Compass No-Start

Car comes in with the complaint engine cranks doesn't start. Confirm the complaint and check for codes, P0688 - ASD Relay Control Sense stored in memory. After doing a quick fuse check I found that ...
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0answers
60 views

Engine diagnostics after engine sucked in water

I have a Great Wall V200 turbo diesel. I was four wheel driving one day when I went through a bit of water. The water came up over the bonnet due to the bow wave. After getting through the water, the ...
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1answer
23 views

98 Toyota Camry: Will night rear light failure trip check engine light?

A number of faults can trip the check engine dashboard indicator and must be checked with an ODB meter to decisively identify the fault. I was just informed that "the car's nighttime rear lights don'...
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2answers
30 views

98 Camry: Check Engine Light at 90K miles [closed]

What is the procedure to address the root cause of the check engine light? Does it make sense to purchase an OBD meter or should some other diagnostic be performed first?
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1answer
22 views

2005 Ford Explorer check engine cod P0446

I have a 2005 Ford Explorer that has a check engine code P0446 which reads as Evap container system vent check malfunction. How do I repair this and where do I start?
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2answers
3k views

What is the “propane test” and how is it carried out?

This test is often mentioned in the context of figuring out what's wrong with a car engine's operation (misfires, hesitation, poor fuel economy, etc.) What is this test and what does one need to ...
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0answers
163 views

Mazda 323 (BJ) 1,5i 16v 1999: OBDI - OBDII ve ELM327

Mazda 323 (BJ) 1,5i 16v 1999 I have a vehicle. I know it uses 17 Pins ODBI. By connecting this to the ELM327 somehow, I want to find the error codes in the vehicle and search for its solution. The ...
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0answers
30 views

Can I learn anything about a misfiring cylinder from the fact that the dialectric grease around the plug is discolored?

On the way to the in-laws yesterday my 2008 fusion started bucking. Code reader says I'm misfiring on cylinder 2. I popped off the coil boots thinking I'd swap them and see if the problem cylinder ...
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1answer
96 views

Siemens sim2k-34vr ecu parametrs and service ids

I need to read parametres like RPM of the engine from siemens sim2k-34vr ECU from obd2 port through K-line protocol,I tried standard service id 0x01 to read current data but ECU said 0x01 service id ...
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0answers
25 views

Manual calculation of engine load [duplicate]

Calculated engine load (PID $04) is determined (according to SAE J1979) by equation: LOAD_PCT = [current airflow] / [(peak airflow at WOT@STP as a function of rpm) * (BARO/29.92) * SQRT(298/(AAT+...
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1answer
160 views

Skoda Fabia 2005: what I need to know to buy a diagnostics machine?

I'd like to buy a diagnostics machine for my Skoda Fabia 2005. My issue is I'm absolutely newbie on this. I don't know which cable connection requires, if there's some standard, ... Will you provide ...
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1answer
23k views

What could be causing a grinding noise when car accelerates quickly?

My son is an hour away and we are trying to diagnose this problem on a 2001 Toyota Corolla. When the car is accelerated slowly and gradually everything is fine. However when the gas "pedal is to the ...
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0answers
28 views

Drop down to zero during ride

Randomly during ride, the "D" from transmission indicator disappears for 2-3 seconds, during this time the car like switched to neutral (RPM raise without acceleration of the car). In the beginning ...
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1answer
134 views

Can you see what version of ELM327 an OBD2 diagnostic scan tool/fault code reader supports?

According to https://en.wikipedia.org/wiki/ELM327#Other_Versions there is a handful of different versions of ELM327. If you buy a non-genuine ELM327-device (that is, something that is compatible with ...
2
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1answer
535 views

Are mineral oil smoke test machines sensor safe?

So there's heaps of DIY smoke test machines demonstrated around the web. I learned to built one of these, was kinda fun. It worked, even found a crack on my air intake that was messing with the ...
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4answers
36k views

Technique to test an alternator - fact or fiction?

A friend explained that the following is a simple way to test an alternator to see if it is working: Turn on the vehicle. While it is running, carefully remove one of the 12V battery leads. See if ...
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1answer
429 views

How do I diagnose trouble code P0567 OBD-II in my car and what are its causes? Which component of cruise control system should be checked first?

I am getting issue with my car's cruise control system, and while diagnosing, this code is shown, I want to know the reason and meaning of this code.
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0answers
218 views

Nissan Qashqai “Test Mode”: What does the data mean?

I learned about a "test mode" for the display, which can be used for diagnostics, without an obd reader. I managed to get inside the test mode, but I am baffled by the data and am not sure what it ...
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1answer
4k views

How To Diagnose 3rd Brake Light (Without Proper Equipment)

I have a 2012 Ford Focus (sedan version). The third brake light stopped working recently and I'm trying to determine if the problem is with the light itself or inside the vehicle, but a I have very ...
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0answers
81 views

Why is this RPM graph squarewave?

'07 Subaru Outback 3.0R 5 speed auto. I am logging using the excellent RomRaider and was kind of surprised that when graphed RPM looks like a square wave in most situations, don't know if it was ...
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3answers
138 views

Developing an OBD2 application - Engine Warning Lights

I am currently developing an application which retrieves diagnostic trouble codes from my car's OBD system and display any DTCs in a list. However, as my car has no trouble codes I am unable to test ...
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3answers
9k views

Possible EGR problem on Fiat Idea Multijet 1.3 Diesel

I've been having issues with my 56 plate Fiat Idea for a while now. It seems to drive normally up to about 2500-3000 rpm where the car lurches a little, as though i shifted down a gear, the MIL light ...
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2answers
15k views

DTC checking while engine running

Why it is said that DTC (Diagnostic Trouble Code) should not be checked when the engine is running?
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10answers
106k views

How can I detect vacuum leaks without access to a smoke machine?

In the course of helping my friend sort out a lean condition with his Mercedes GLK280 we have to pinpoint the source of a vacuum leak in the intake plumbing. The interwebz tend to recommend having ...
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3answers
55k views

How to diagnose the cause of no power reaching the spark plugs when power reaches everything else, after checking fuses?

I've been trying to get my long-suffering Toyota RAV4 first generation (1998) to start after numerous different problems, the latest of which I've narrowed to the spark plugs not firing seemingly due ...
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0answers
14 views

Konnwei kw30 diagnostic equipment

Just got a konnwei kw830 diagnostic tool I plug it into my car which I know has a fault as I have checked on another system and that comes up with fault key 1 which means my car key has lost its ...
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1answer
6k views

How to check if spark plugs are firing? Coil-on plugs

While trying to diagnose a tricky car not starting problem I was asked to check if the spark plugs were firing at all. I've found plenty of resources on inspecting the condition of spark plugs after ...
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1answer
133 views

Need help with diagnosing weak AC on ford explorer

2007 Explorer has weak AC. When driving at speed, the AC can produce reasonably cool air. When stopped at traffic lights or such, the air warms to ambient temps rather quickly. I hooked up the ...
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1answer
63 views

What things are tested during a diagnosis for a sluggsh engine?

I enquired at both dealer and garage about diagnosing my car for being a bit sluggish and less peppy. Both said it usually takes one hour to find the problem\narrow it down for such a matter. I'm ...
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1answer
54 views

My Octavia 1.9 TDI 2004 not won't cross 120km

My car would not cross 120 km. What is the problem? What is maximum speed of the 2004 Octavia 1.9 TDI engine superup