42
votes
Accepted
Difference between OBDII and CAN
Ok, before I will answer your specific questions, let's do some introduction on bus systems. It could be that you know parts of these things, but I will start here as people with little or no IT or ...
- 1,301
23
votes
Accepted
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-...
- 153k
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:...
- 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 ...
- 8,672
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 ...
- 121
11
votes
Is control module voltage and battery voltage the same?
Looks like the issue is with the incoming signal.
Unless your vehicle comes equipped with a flux capacitor, 65 V across battery is a bit too much. Even heavy trucks don't run that voltage to my ...
- 39.1k
11
votes
Accepted
Disabling OBD2-Interface in a car
You're glossing over how the hack actually happens. The hack involves erasing the old keys and then reprogramming a new key to the vehicle. If the car uses a smart key then you're in right away. If ...
- 16k
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 ...
- 16k
10
votes
Accepted
Is it possible to auto close the power window of a car using OBD and CAN bus?
Everything depends on if the manufacturer multiplexed the windows or not.
For example, General Motors tends to multiplex their windows. This means that every door has a module inside it. The module ...
- 16k
10
votes
Accepted
What is the motorcycle equivalent of OBD-II?
Some motorcycles have a CAN BUS, some don't
The OBDII connector type is simply a standard instituted by the SAE (Society of Automotive Engineers). In 1996 the US government mandated that all cars ...
- 33k
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 ...
- 895
10
votes
Accepted
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 ...
- 12.4k
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 ...
- 153k
9
votes
Accepted
How to detect engine/ignition (on/off) status using OBD2?
Everything depends on exactly what your looking for.
If engine running/not running is sufficient then check the RPM. If RPM is non zero, the engine is running. If the RPM is zero or no communication ...
- 16k
9
votes
Difference between OBDII and CAN
OBD II is a US government mandated diagnostic interface. This interface is guaranteed to provide a specific set of information including but not limited to engine computer data and engine computer ...
- 16k
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) ...
- 251
8
votes
ATMA on OBDII not Working
Did you set the protocol for the chip to monitor on? e.g. ATSP5 for KWP-2000 or ATSP0 for "best guess". What about checking the headers as well - ATH1?
I use the following string of commands to ...
- 1,945
8
votes
OBDII ELM 327 Bluetooth adapter - is it reliable?
The ELM327 is (almost?) as powerful as any other diagnostics solution. That's simply because it only translates the low level OBD protocols to some other format.
Bluetooth connections on mobile phones ...
- 307
8
votes
Accepted
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 ...
- 9,326
8
votes
Accepted
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, ...
- 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.
- 3,072
7
votes
Any open-source OBD scanner analysis tools?
There's a lot of work going on in this space, so the answer is "Yes, Of course!"
Here is a Python project: http://www.obdtester.com/pyobd
This looks like an interesting way to get data from the car, ...
- 13.3k
7
votes
Accepted
OBD II power when key not in ignition
Pin 16 on the ODB-II connector is specified as "Battery Power" or "Battery Positive". There will always be 12v power between pin 4 and 16. Note that pin 5 has "ground" in the description, but that ...
- 13.3k
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 ...
- 24.9k
7
votes
Accepted
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 ...
- 86
7
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 ...
- 39.1k
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.
- 24.9k
7
votes
Accepted
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 ...
- 9,999
7
votes
Accepted
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 ...
- 3,790
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 "...
- 153k
Only top scored, non community-wiki answers of a minimum length are eligible