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
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
10
votes
Accepted
Horsepower at wheels calculation
TL;DR
The problem you are encountering is the limited resolution of your speed plus fluctuation plus slightly different approaches to calculate power. And finally, you have to think about the term ...
- 7,047
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.
- 3,032
7
votes
About heavy-duty vehicle diagnostic port
Isn't it a standard, so all vehicles are wired the same (for a given connector)?
The following information comes from the Handbook of hardware schemes, cables layouts and connectors pinouts website.
...
- 1,848
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
5
votes
OBD or CAN - what's mandatory (EU and US)
I believe you are confusing CAN and OBD.
CAN is an electronics interface protocol. Short for Controller Area Network, CAN allows for expandable interconnected systems, so you can add new sensors and ...
- 781
5
votes
Horsepower at wheels calculation
Two things to watch out for when using these equations
Consistency of units
If your mass is in kg, speed in km/h and acceleration in furlongs per week², you're not going to get power in horsepower. ...
- 39.1k
5
votes
Mode 02 - Freeze frame data use
While the fault code that popped the MIL is tremendously useful by itself, freeze frame data offers huge help, as it allows you to see the exact conditions under which the engine decided that there is ...
5
votes
Accepted
Retrieving handbrake status light and reverse light from OBD II
Start off with a copy of the service manual for your car. The electrical schematics will help you understand where the various annunciators come from. Earlier cars typically have less data available ...
- 14.4k
5
votes
What is the point of performing an OBD2 diagnostic scan if there is no malfunction indicator?
Not all diagnostic messages ("error codes") detected by the car computer manifest by a light on the dashboard.
Some of them light the "check" lamp until they are cleared.
Some of ...
- 2,022
4
votes
Accepted
Auto determine the bluetooth device is OBD or not?
Each bluetooth device has a unique 48 bit address and a device name (up to 248 bytes). The name is usually shown when doing a bluetooth scan with a mobile device. The only way you can tell the ...
4
votes
Accepted
Relation of VIN of a car with emission norms of a country it is sold
Cars are manufactured to meet the emission standards of the country it is intended to be sold in. If the car was manufactured in Canada with the intent to be sold in India, it will be designed to meet ...
- 12.2k
4
votes
OBD MIL commanded status and DTC stored
Not all DTC's will activate the CEL
It is up to the manufacturer whether or not to trigger the Check Engine Light based on the Diagnostic Trouble Code, so a misfire DTC is not the treated with the ...
- 39.1k
4
votes
OBD-II Mode and PIDs specifically used for Electric vehicles?
It seems like every (lots of people on this forum) one is mixing up what OBD is and what CAN is.
OBDII is a standard ratified in 1996 in the US. This standard is required by the government and ...
- 16k
4
votes
Accepted
Siemens sim2k-34vr ecu parametrs and service ids
I found its PIDS is under MODE 0x21 and PID 0x01, I hope it helps to other peoples.
- 51
4
votes
How useful is a low-end corded OBD-II reader for inspecting a used car?
It's going to be of limited value - which isn't to say none. Given most codes that are serious enough to really be of concern (and quite a few that aren't) are going to cause the Check Engine Light or ...
- 9,989
4
votes
How useful is a low-end corded OBD-II reader for inspecting a used car?
If you plan to take the car to a professional mechanic for an inspection having your own reader is unlikely to be that much use, although it's not a complete waste of time. It may help determine ...
- 16.2k
3
votes
What do all these codes mean? 125331324255
The way to read the codes on your Jeep when they are flashing is, consider them blocked into two digit numbers. You'll get the first digit flashed, short pause, then the second digit. If there is more ...
- 153k
3
votes
Could you instruct a car thru the OBD port to open the trunk even if the car was turned off?
According to this response, when the ignition key is removed from the car it's usually not possible to communicate with the car via the OBD port so assuming by "turned off" you mean the ignition key ...
- 23.5k
3
votes
What is Honda HDS HIM?
HDS HIM stands for Honda Diagnostic System - Honda Interface Module. This is the current HIM. It interfaces with a PC to run scan tool software and is a standalone module reflash unit. It requires a ...
- 11.6k
3
votes
Mode 02 - Freeze frame data use
We find FF so useful that we retain it on the customers invoice in case the same code sets later. It is also very helpful when used in conjunction with a test drive on intermittent faults. It tells ...
- 11.6k
3
votes
Mode 02 - Freeze frame data use
They help us home in on what might be the root cause
Maybe an example would help explain why freeze frames are so useful
Here is the P0300 freeze frame from that infamous Merc GLK280:
+-------------...
- 39.1k
2
votes
Retrieving handbrake status light and reverse light from OBD II
You will not be able to read everything using OBD. Sometimes you can be lucky and the proprietary protocol your car uses can provide you with the right info, however this wouldn't be reliable as it ...
- 191
2
votes
Fault code decoding
Mode 6
This mode gives the results of self-diagnostics done on systems not subject to constant surveillance.
AA Misfire data cylinder 9
The Volvo-a lot those codes are exhaust gas sensors etc
...
- 3,917
2
votes
Emission performance of a vehicle using OBD
OBD2 style emission testing makes one very large assumption.
If every system is working properly then the car is not polluting.
This is verified in two ways.
If the computer has any hard fault ...
- 16k
2
votes
Accepted
What is Honda HDS HIM?
Actullay the picture above is not a Honda HDS HIM interface, it's a Honda MVCI interface.
Honda HDS (Honda & Acura Diagnostic System) is the latest diagnostic software for Honda vehicles. ...
- 56
2
votes
Accepted
How to save time history of cars' performance parameters with or without OBD
The easiest and most accurate thing you can do is buy something like a Racelogic data logger as it's a piece of hardware that's specifically designed for the exact purpose you describe.
- 23.5k
2
votes
Accepted
Oxygen Sensor Engine Light
If a code came up and you cleared it without fixing it, it will come back. Once you clear a code, the computer resets the Readiness monitors and start to conduct a new drive cycle test routine. Since ...
- 1,372
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