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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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 ...
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293 views

How do I diagnose a blinking overdrive off light on a 2001 Ford F-150 with 4R70W transmission?

Today the "OFF" light on the transmission shifter starting blinking on my 2001 Ford F-150. It is the 4.6L with a 4R70W transmission. I pulled the codes but all I found was "Evap system inoperative" ...
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35 views

98 Chevy Malibu 2.4 liter has fuel and fire but will not start

98 chevy malibu 2.4 liter .Has fuel to injectors and fire to the plugs but won't start?
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318 views

Difference between black and blue eml327 diagnostic tool

I've recently bought an Alfa Romeo 147 1.6TS 2001 105hp(77kw), and the previous owner had an instrument, or gauge, or mileage table replaced along with electrical window and mirror button table on ...
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1answer
40 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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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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1answer
90 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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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
37 views

Won't go when out in gear [closed]

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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1answer
32 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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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
55 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
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3answers
278 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 ...
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1answer
267 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
40 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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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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100 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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74 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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67 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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26 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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241 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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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
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
100 views

Electrical Diagnostic Procedural Lists [closed]

Post your general/specific Testing/Diagnostics Procedural Lists for Automotive Electrical Systems. These procedures are intended to target vehicles with modern 12V systems. The format of the site ...

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