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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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Detecting moisture source inside a car

The inside of my BMW E46 M3 is damp, and I want to trace the source of the moisture so I can stop it. I know of some of the common sources of damp inside these cars, for instance it's a convertible so ...
GdD's user avatar
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3 votes
3 answers
549 views

Any insights or tips on 2012 Mini Cooper S Coupe Random Misfires?

UPDATES 2: I ended up changing the HPFP which I got from eBay for half, the ignition coils, oil filter, air filter, spark plugs, and I put in the bypass for the faulty airbag sensor (all thanks to ...
Tommie C.'s user avatar
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0 answers
34 views

Car Stalls After Running AC Heating System

My 2011 Nissan Rogue is stalling out on me. The first time this happened was after going over a speed bump in heavy snow - I sent it to a garage and they told me that there were "No OBD Codes To ...
Zibbobz's user avatar
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1 answer
112 views

Do ODB-II/EODB/JODB readers for dealers/mechanics show more than consumer readers?

When you go to an auto parts store and buy an ODB-II/EODB/JODB code reader, you will be buying a device that will read vehicle fault codes via a standardized data port. Do vehicle manufacturers sell ...
End Antisemitic Hate's user avatar
2 votes
3 answers
374 views

Cannot view some data with VW OBD2

i have a vw golf mk6 2009 2.0 tdi 110cv, i have had this small problem with ABS turning on and off intermittently and got me down this rabbit hole of trying to get data from car and understanding it. ...
sgt's user avatar
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1 answer
47 views

What does an NG Ground Fault error status indicate?

This is for a Honda Clarity 2018 PHEV non-touring. Error shows up in the diagnostics screens. EDIT: adding photos... Furthermore, it should be noted that while the error appears to be persistent (I ...
Arctiic's user avatar
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2 votes
1 answer
42 views

Can deposits on glow plugs be used to diagnose engine problems?

In a gasoline engine deposits or discoloration on spark plugs can be used to diagnose problems, for instance lean or rich running, or ignition problems. There are many handy pictures available to show ...
GdD's user avatar
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2 votes
2 answers
201 views

Why OBD2 reader when cars have digital display?

I can see why separate OBD2 readers were needed before cars had a digital display. But now that they all do, why can't they just display the CEL code on the display instead of having to use a separate ...
amphibient's user avatar
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2 votes
1 answer
124 views

What's going on with the "temperature" part of this pressure gauge?

Ok, I think I finally understand the pressure bit of this gauge that came with this set of poorly documented hoses I got off Amazon. From 0 to 350, it's actually measuring pounds per square inch (PSI)....
lly's user avatar
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1 answer
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What can I learn about a vehicle's "health" from analysis of audio recordings?

Suppose I can record audio of a vehicle near different points (e.g. beside the engine or exhaust) during different activities (e.g. revving, idling, starting), and suppose I am well-equipped with ...
Galen's user avatar
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472 views

Distinguishing bad alternator diode from short

Is there a good way without disassembly to distinguish between an alternator with a bad diode and a high resistance short in the alternator (between the output and housing) caused by moisture/...
R.. GitHub STOP HELPING ICE's user avatar
1 vote
1 answer
751 views

DTC B1227 - An open in outside temperature sensor circuit - AC not working

I have Acura RDX 2007 and the AC does not work. I took it to dealership/mechanics and they saw that the outside air temp sensor somehow banged condenser and had to replace the condenser. The ...
Joseph Phronesis's user avatar
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0 answers
71 views

mechanic can't reproduce trouble when car is at shop... need to record OBD data when problem occurs while driving

I brought my car in for servicing, but the mechanic can't reproduce the problem. I want to log OBD data as the problem occurs. I would then provide this captured data with the car when it goes back ...
TRS-80's user avatar
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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 ...
DrMickeyLauer's user avatar
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2 answers
917 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 ...
WGroleau's user avatar
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4 votes
1 answer
5k 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. ...
ajayel's user avatar
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0 answers
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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
Baron's user avatar
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1 answer
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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 ...
yigal's user avatar
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0 answers
87 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 ...
James Wilson's user avatar
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939 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 ...
Sandy's user avatar
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0 answers
721 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 ...
FatSumo's user avatar
0 votes
1 answer
51 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 (...
Bubba's user avatar
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0 answers
258 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 ...
ElectronicsNewbie's user avatar
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0 answers
155 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 ...
Tyler Haddin's user avatar
0 votes
1 answer
32 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'...
gatorback's user avatar
  • 1,267
0 votes
2 answers
45 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?
gatorback's user avatar
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0 votes
1 answer
63 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?
Brian Wambold's user avatar
1 vote
0 answers
1k 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 ...
Fatih ATEŞ's user avatar
1 vote
0 answers
35 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 ...
Sidney's user avatar
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0 votes
0 answers
61 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+...
Rafal's user avatar
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1 vote
0 answers
31 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 ...
ChaosPredictor's user avatar
1 vote
1 answer
228 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 ...
Amin Rezaie's user avatar
0 votes
1 answer
736 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 ...
d-b's user avatar
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0 votes
0 answers
830 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 ...
user1721135's user avatar
3 votes
2 answers
1k 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 ...
asp316's user avatar
  • 211
1 vote
0 answers
31 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 ...
Graham Kennedy's user avatar
0 votes
2 answers
110 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 ...
James Wilson's user avatar
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0 votes
1 answer
74 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 ...
James Wilson's user avatar
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2 votes
1 answer
227 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 ...
Falcon's user avatar
  • 21
8 votes
1 answer
446 views

Exactly how much refrigerant is in there?

A concern that comes up regularly when troubleshooting A/C problems is whether an A/C system has too little refrigerant (hello leaks) or too much of it (hello overcharging). The traditional way to do ...
Zaid's user avatar
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2 votes
0 answers
95 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 ...
ajayel's user avatar
  • 484
2 votes
2 answers
189 views

Need Help Diagnosing and Fixing my Kawasaki Ninja

First time poster here. I have a 2010 Kawasaki Ninja 250 - this is a bit of a story and I try and keep it short. A couple weeks ago my bike was having trouble - when I would rev the engine in low ...
Ely's user avatar
  • 21
0 votes
1 answer
73 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
Amir Kasdiya's user avatar
2 votes
1 answer
1k 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 ...
ajayel's user avatar
  • 484
3 votes
1 answer
239 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 ...
user7264855's user avatar
1 vote
0 answers
98 views

Check engine light won't stay off

I've attempted to get my check engine light fixed a couple times and at each repair facility they've scanned the code and told me it was a bad oxygen sensor. I had the oxygen sensor replaced at both ...
public wireless's user avatar
0 votes
3 answers
405 views

Brake problems with 1991 Toyota Celica

I have no brakes. I have bled the brakes, changed the pads and calipers, brake hose. The front driver side bled with no problems but the passenger won't. What else could it be? I've also replaced the ...
Jennifer Lynn Mcguire's user avatar
1 vote
0 answers
7k views

Replaced transmission now car wont start

Had my transmission replaced drove car for three days now it won't start. Lights and radio work. No crank no start. Replaced battery, starter, and starter relay. PLEASE HELP HAVEN'T HAD MY CAR A YEAR ...
Amber Owens's user avatar
2 votes
0 answers
399 views

2006 Mazda MX-5 P0126 + B1318

2006 MX-5 57k Miles USDM 2.0L 6-Speed P0126 and B1318 Set but no light on/Sporadic illumination. Coolant reservoir is full. https://www.obd-codes.com/p0126 That site references that there's a TSB ...
NitrusInc's user avatar
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4 votes
2 answers
606 views

Toyota Vitz 2007: Can a vacuum leak lead to PO171

In my Toyota Vitz 2007 (Yaris in some countries), I sometimes get a PO171 (System too lean) trouble code when the vehicle is idling in a traffic. When my mechanic scanned the vehicle for trouble ...
Softcode's user avatar
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