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23 votes
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What is the point of performing an OBD2 diagnostic scan if there is no malfunction indicator?

In most cases, unless things have been cleared, there's a good chance that if there was an issue previously, the codes will still be present in the ECU. Some codes are permanent (well, semi-quasi-...
Pᴀᴜʟsᴛᴇʀ2's user avatar
13 votes

Is it safe to get power from OBD 2 port for dash cam?

Maybe not answering your question completely, but: some people doubt how the OBD II connector is connected to power. The specification (SAE J1962 specification) of the connector is quite clear on this:...
Bram Vonk's user avatar
  • 131
12 votes

How useful is a low-end corded OBD-II reader for inspecting a used car?

There is a place where this reader can be useful. Know the age of the car, and your state regulations, to find out how many 'Not Ready' monitors are allowed before the car will fail emissions. If ...
PeteCon's user avatar
  • 8,712
12 votes

What is the point of performing an OBD2 diagnostic scan if there is no malfunction indicator?

Sometimes second-hand car sellers turn off or remove warning lights from dashboard in order to hide some problems, rather than spending money to fix them. Therefore, an OBDII diagnostic made by a good ...
Tinel Barb's user avatar
11 votes
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Do fault codes get recorded with a time stamp into a log with a history of DTCs?

It really depends on the implementation of OBD2. What my 1997 Subaru logs (virtually nothing) compared to a 2015 Chevy Cruise are entirely different things. However, in most cases, a Diagnostic ...
SteveRacer's user avatar
  • 12.4k
11 votes

How do I go about troubleshooting DTC codes?

The computers in a car are constantly monitoring the operating conditions and sensors that are in the car. When a test fails or something goes out of a pre specified range a DTC is set. The biggest ...
vini_i's user avatar
  • 16k
10 votes

Difference between fuel pressure and fuel rail pressure

On a car with fuel injection there can be two fuel pumps, one high-pressure and one low-pressure. The low-pressure pump moves the gas from the tank up to the high pressure pump. The high pressure ...
Ukko's user avatar
  • 885
10 votes

Would OBD-II devices drain the battery when used 24/7?

If the engine isn't running, then they surely will. I have an ELM 327 (Bluetooth) device which plugs into the OBDII port. Even when the vehicle is turned off, the device is active. Before I realized ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
9 votes

What does it mean when the ELM327 OBD2-reader gives two lines of info for 0100 request?

try this AT H1 this will turn on headers, then do 0100 you will get something like 7E8 06 41 00 BE 3E A8 13 7E9 06 41 00 98 18 80 13 which says you are getting results from ECUs 7E8 (engine) ...
godzilla's user avatar
  • 251
8 votes
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Controlling door lock/unlock via CAN bus

The OBD-II port supports a number of electrical protocols, but all of them are serial in nature. There is nothing you can do to any of the OBD-II pins with "plain negative pulses" to do what you want ...
cdunn's user avatar
  • 9,296
8 votes
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OBD-II difference between signal ground and chassis ground

You are over thinking things, just connect your devices (OBD & Pi) to a good chassis ground: The difference between chassis and signal ground is: Chassis Ground Pin 4: Is exactly that, ...
Newbie Noob's user avatar
  • 2,781
8 votes

What is the point of performing an OBD2 diagnostic scan if there is no malfunction indicator?

He can also look at fuel trims and other sensors performance. Some conditions on an engine may be efficient enough to keep the engine light off, but not in an ideal range.
Jupiter's user avatar
  • 3,222
7 votes

Can we determine the Cleaning Requirement of Air Filter Using OBD

Modern gasoline engines have sensors to measure the amount of air that enters the engine. The ECU then injects fuel to give the correct mixture to get the most efficient burn. A dirty air filter ...
HandyHowie's user avatar
  • 25.2k
7 votes
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Is it Possible to Control Lights through OBD-II Port?

The short answer is: no - not without the manufacturer's diagnostic tools. The long answer is: maybe. Modern cars have most (if not all) exterior and interior lights controlled by the body control ...
Andrew's user avatar
  • 86
7 votes

What is the point of performing an OBD2 diagnostic scan if there is no malfunction indicator?

You can have intermittent errors logged that will not cause the MIL to illuminate, so that could be a valid reason to get the codes read.
HandyHowie's user avatar
  • 25.2k
7 votes
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Determine which features of a car are software locked

For your Skoda and other Volkswagen Audio Group (VAG) vehicles probably the simplest way is to use something like OBDEleven, this uses what they term "One-Click-Apps" to update the necessary ...
motosubatsu's user avatar
7 votes
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Golf 7 key stolen, which fuse to remove to disable car key reprogramming?

There is no fuse to remove that will disable immobilizer programming. You can how ever remove the fuse for the obd2 power. That will slow someone down since their tool would no longer be powered and ...
narkeleptk's user avatar
  • 3,780
7 votes

Should I clear Prius ODB-II codes?

The first thing I do when checking any vehicle is to clear the codes, that way I can see what comes back up afterwards. Those are the codes you look to see what issues the car might have. So "...
Pᴀᴜʟsᴛᴇʀ2's user avatar
6 votes

Received frames from vehicles with multiple ECU chips

If your vehicle is 2008 or newer it is using the can protocol, you can use the AT CR command to select which ECU you want to hear from. Here's how: send AT H1 this will turn on headers to see the ...
godzilla's user avatar
  • 251
6 votes
Accepted

Nitro OBD2 SCAM OR WORK?

Some just READ data from the OBD2 port. Others like the DiabloSport handheld tuner can modify the engine tune IF the model supports it. I have no idea if the NitroOBD2 gadget does anything it claims ...
race fever's user avatar
  • 3,353
6 votes
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Tapping into the on-board computer

You cannot easily "tap" into any ECU/PCM. Depending on what year your vehicle is, it could be a simple set of analog gauges which you could tap into the signal line, but you'll need to do some ...
DustinDavis's user avatar
6 votes

2000 chevy cavalier cheap upgrades

If the question emphasis is on cheap, weight reduction is your friend For many reasons: A lighter car accelerates more quickly Because physics. Since you're planning to drag race, top speed should ...
Zaid's user avatar
  • 39.1k
6 votes
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Cannot Access ABS-control-unit with ODB2-adapter

To my knowledge, access to the ABS module will not be possible through a generic OBDII adapter. The most commonly available option for VW's of this era is a VAG-COM cable with RossTech software on a ...
Zaid's user avatar
  • 39.1k
6 votes

OBDII across the world?

I found this informative web site which explains it well: There are five basic OBD-II protocols in use, each with minor variations on the communication pattern between the on-board diagnostic ...
CharlieRB's user avatar
  • 9,015
6 votes

OBD II Scanner refuses to communicate with the vehicle!

Courtesy of a SNAPON document If the scan tool does not receive data from an OBD II vehicle TEST 1: Connect the positive DMM lead to DLC pin 4 and the negative DMM lead to the negative battery ...
ElectronicsNewbie's user avatar
5 votes

Is Torque App reliable to read O2 sensor data?

The upstream o2 on a Prius is an AFR sensor stoich reading at idle is 3.33 volts. The application isn't able to read the correct PID. So of course it would read 0v all the time.
Ben's user avatar
  • 10.7k
5 votes

Stopping distance of a car

You cannot. You can't even do it that well with GPS. The only relevant OBD2 parameters are speed and RPMs. If the wheels are locked or traction is otherwise lost, neither of these can be used in the ...
Jason C's user avatar
  • 4,890
5 votes
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Is it possible to access multiple CAN buses through the OBD-II port?

I figured it out. The answer is manufacturer dependent. The OBD-II diagnostic port has a number of pins which are listed as "Vendor Option". The manufacturer may choose to connect one or more of these ...
Moeman69's user avatar
  • 393
5 votes

Can a vehicle be harmed with bad inputs via an OBD-2 port?

Just this morning I connected an ELM327 to a '05 Volvo XC90. After only 1km, the message was displayed for "Anti-skid service required", and then "Anti-skid temporarily unavailable". I removed the ELM,...
Pete T.'s user avatar
  • 51
5 votes

Need explanation on Commanded EGR and ethanol%

Ethanol % PID is the cars best guess at the ethenol level is in the fuel. This is more common on E85 Vehicles. Commanded EGR is what the car wants the EGR valve position to be at, not all cars have ...
Ben's user avatar
  • 10.7k

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