On-Board Diagnostics-II (OBD-II). Questions usually involve scan tools, their use and their compatibility, as well as how to interpret Diagnostic Trouble Codes (DTCs).

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5
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1answer
45 views

Difference between fuel pressure and fuel rail pressure

In OBD PID wiki page, there are 2 PIDs listed: Fuel pressure and Fuel rail pressure. Are both of them the same? Can someone please give an elaborate explanation of it - What exactly are they ...
2
votes
0answers
43 views

How to calculate Car “Distance Till Empty” without knowing the fuel level

I've Renault Duster RxZ. I would like to calculate the DTE(Distance till Empty) which is based on the "how much fuel the car has" and the "mileage of the car" ? Currently the OBD doesn't return ...
5
votes
1answer
54 views

Disabling OBD2-Interface in a car

If a car-thief wants to steal a modern car, he often uses the OBD2 (On Board diagnosis) to "hack" the car. Simplified: He achieves this by plugging his "hacking device" in the port, which aquieres ...
3
votes
1answer
30 views

Engine Temperature from OBD data

Engine Coolant temperature is obtained from OBD. But there is no PID to get engine temperature. Obviously, they are related, rather proportional I guess. But can there be a case where my engine is ...
5
votes
1answer
670 views

OBD 2 Fuel reading says No Data

I wanted to read fuel level from the car and display it on my application. The communication was established using the ELM327 Bluetooth interface dongle. The ELM module replies NO DATA for the code ...
15
votes
2answers
771 views

Difference between OBDII and CAN

What is CAN (controller area network)? What are the differences between an OBD-II protocol and a CAN setup?` How do I use an OBD-II scanner on a vehicle with CAN?
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vote
0answers
45 views

Stopping distance of a car

I want to calculate the stopping distance of a car from an OBD2 device. Say, I am driving at 30 kmph and apply my brakes hard. My car will skid and stop at a distance "x" meters from that point. This ...
3
votes
2answers
44 views

Can the throttle position be high during idle

I used an OBD to get data from one of my friend's car - Volkswagen Polo 1.5L Diesel. But the car was idling at around 900 rpm, while the throttle position I got was around 22%. How is it possible? As ...
1
vote
2answers
84 views

Formula to calculate emission rates

OBD tells whether I have passed the emission test or not. I want to know the formula by which it calculates the rate of CO, NOx, HC emission from my car and compares it with some set threshold value ...
14
votes
3answers
581 views

What are good features to look for in an ODB-II reader

I recently took my car in for the engine light. It turned out to be a minor problem (crack in gas cap let water in). It would be nice to have a low-cost ODB-II reader to be able to find out for ...
2
votes
1answer
43 views

Expose Car Hardware information

I am looking for way via which i can access my car information when it is running like speed,acceleration,gear information,oil information,etc . My Car details : Hyundai Verma : Model 2006 , Manual ...
3
votes
2answers
110 views

OBDII ELM 327 Bluetooth adapter - is it reliable? [closed]

I got myself such a bluetooth adapter for my car, because the display on the radio stopped working, and I wanted to see if it will show up any errors. There are even apps for Android that work with ...
11
votes
1answer
72 views

Are there any plans to update OBD-II?

OBD-II is ancient It predates the Porsche 911 GT1, Windows 95 and implementation of the Schengen Agreement. I would have thought that SAE would be working to add more diagnostic coverage for ...
6
votes
1answer
66 views

ATMA on OBDII not Working

I have successfully connected a terminal android app to the obd port of my car. And tried dry run of many at commands, many are working as expected. But ATMA (AT command to Monitor All) is not ...
8
votes
1answer
57 views

Computing Wheel Torque From Engine Torque

It seems possible to obtain engine torque and RPM from a truck CAN bus. I'd like to estimate tractive force at the wheels given these two values. How should I go about computing torque at the wheels? ...
11
votes
2answers
97 views

What is the motorcycle equivalent of OBD-II?

I once met an OBD-II expert while traveling and asked him if motorcycles (especially the fuel-injected ones) employ a similar protocol. He said that the use of such a protocol is not as widespread ...
4
votes
2answers
633 views

OBD II power when key not in ignition

I can't get to the OBD connector on my car at the moment. As far as I know the OBD II voltage is active even when the key is in lock. Can anyone confirm this? edit : It's for a product that ...
3
votes
2answers
144 views

Wheel alignment from OBD parameters

Can I calculate wheel alignment from OBD parameters. Car is Hyundai i10, and it doesn't give any Steering Alignment/ Steering Position data. The only method to check the alignment is to let the car ...
4
votes
1answer
30 views

Calculating AFR using injector flow rate and mass air flow

Is injector flow rate = Mass fuel flow? If so then AFR = MAF/Injector flow rate. Can someone please confirm this?
1
vote
1answer
31 views

Auxiliary input status and Auxiliary input / output supported OBD2 PID

I want to know what does Auxiliary input status (PID 1E) and Auxiliary input / output supported (PID 65) OBD2 PID mean. Do they tell me whether my car is in the Aux mode (while I am listening to the ...
5
votes
0answers
48 views

Mahindra KUV 100 and Suzuki Alto OBD protocol

Can someone please tell me the OBD-ii protocol of Mahindra KUV 100 (diesel) and Suzuki Alto (diesel). Also whether ELM 327 Bluetooth will work? ...
5
votes
2answers
42 views

Calculate amount of fuel injected

How do I calculate the amount of fuel injected (both gasoline and diesel cars). I want an instantaneous value. http://www.rceng.com/technical.aspx Websites like these ask for 'Desired Crankshaft ...
2
votes
0answers
21 views

Calculated vs absolute engine load [duplicate]

The OBD-II protocol (SAE J1979) has a couple of PID's that relate to engine load: +------+-----+---------------------------------+ | Mode | PID | Description | ...
4
votes
2answers
54 views

Gear ratio from speed and rpm

http://stackoverflow.com/questions/30017271/obdii-determine-gear-given-speed-and-rpm Referring to the above link, one method to find the current gear ratio is to calculate Speed/rpm (The rpm is the ...
5
votes
1answer
25 views

On-Board Diagnostics (OBD) Readiness Monitors

I would like to know how does apps like Torque calculate if my car (Hyundai i10 Era) is 'Not ready' yet? What are the factors (complete list) do one checks to decide? Is there any formula to calculate ...
5
votes
2answers
103 views

How is barometric pressure related to emissions testing?

In the VW emissions cheating scandal, news reports say the following: According to the EPA, "the position of the steering wheel, vehicle speed, the duration of the engine's operation, and barometric ...
4
votes
0answers
117 views

Acceleration problem, but only immediately after stopping

Symptoms: The following applies mainly when accelerating from zero speed at 1st gear in RPM below 2500. Above that RPM range, there is no problem (then acceleration is assisted by turbo-compressor). ...
3
votes
0answers
977 views

Mercedes Atego OBD2 live data codes

I have tried to connect an OBDII ELM327 adapter in Mercedes Atego. Somehow I managed to get it in that OBD2 connector. I can see that my adapter is receiving electricity. These are the PID's that I ...
7
votes
4answers
296 views

Is control module voltage and battery voltage the same?

Is the Control Module Voltage (from OBD Mode 01 PID 42) and battery voltage the same? If not, what is the relation between them? Why is the max value of Control Module Voltage (from OBD Mode 01 PID ...
4
votes
1answer
114 views

Is it possible to auto close the power window of a car using OBD and CAN bus?

I am not an electrical or automobile engineer, so pardon my ignorance. I found this product in the market to auto close power windows for certain brands. How can we send signals to the CAN bus using ...
9
votes
1answer
199 views

How to detect engine/ignition (on/off) status using OBD2?

My device needs to know when a car engine/ignition is started and stopped. Is it possible to get that status using OBD2? If yes, which PID will give me that information? Do I need to write any ...
1
vote
4answers
78 views

What good is a scan tool?

Other than reporting error codes, is a scan tool useful? Can it help you to tune the car to optimize gas mileage for example or other helpful things?
3
votes
1answer
30 views

Android App for ELM 327 that allows to reset codes for Cadillac CTS

On my Cadillac I get engine light to come up because I have changed my petrol cap and sensor is malfunctioning. I got myself wifi ELM 327 OBD-2 reader, and by using my laptop I managed to get RPM of ...
2
votes
1answer
62 views

CO, NOx, HC plot with AFR Table [closed]

Can someone provide me with a lookup table (reliable of course), or a plot (with exact plot to scale) for CO, NOx, HC emission from a SI engine? If possible, I am also looking for the same with for ...
2
votes
1answer
86 views

Determining active gear from OBD2 for Ford Fiesta

I am trying to to write an app which advises the driver to change gears and do some other driving quality assessments. For this purpose I need to determine the RPM and currently active gear in a ...
8
votes
3answers
191k views

What is the pin or keycode for ELM327 bluetooth OBDII adapter?

The infamous ELM327 OBDII device came without any paper, just a crappy CD with no document related to the device (only some software and drivers thrown on the CD almost randomly). I tried the ...
1
vote
3answers
64 views

Oil pressure and fuel pressure formula

Can someone give me a formula to calculate Oil and Fuel pressure of a car engine? Consider a small passenger car. I have information like Total distance travelled, speed, rpm, MAF, MAP, Intake Air ...
1
vote
2answers
60 views

Can a universal catalytic converter be legally fitted to my Prius in California?

My 2006 Toyota Prius with 280k miles is throwing the P0420 code, which means that it (probably) needs a new catalytic converter. I live in California, which makes life much more difficult to replace a ...
1
vote
1answer
274 views

Error Message from OBD-II (7F 01 11)

I have been extracting OBD-II DATA from UART board (ELM327) on my TOYOTA INNOVA. It responded correctly few weeks before and gave all supported sensor values. But now, for every response, ECU responds ...
2
votes
1answer
64 views

Calculate tyre pressure of a car from OBD parameters

I want to calculate the tyre pressure of a car from OBD parameters. I don't want to take TPMS or any custom PID for this. One of the indirect method is the calculate: ((w_LF + w_RR) - (w_RF + w_LR)) ...
3
votes
1answer
125 views

How can one calculate volumetric efficiency without a MAF sensor?

I am completely new in the field of OBD2 sensor; I am looking for a method (or a formula) to calculate Volumetric Efficiency of: Diesel Car Petrol Car which do not have a MAF sensor. Can anyone ...
2
votes
1answer
49 views

Getting MIL on a Dodge Grand Caravan 2012 without an OBD device

I have a dodge grand caravan 2012 and yesterday, the check engine light went on. I know there's usually a way to get the error codes without an OBD device... I was able to do this on my old caravan ...
0
votes
1answer
46 views

Calculate car battery life using OBD parameters

I want to calculate the battery life of a car based upon OBD2 parameters like engine load, distance traveled, Control Module voltage etc. Can anyone please guide me as to how to do this? If ...
1
vote
2answers
48 views

linking a phone to a car via OBD-II and Bluetooth: Automatic (1st gen) in Europe [closed]

I am relocating to Europe soon, and I'm pretty sure my new car would have OBD-II. Why is Automatic adamant their current product is for the US only? Is it a regulatory issue, or something technical ...
4
votes
1answer
89 views

OBD-II reader has power but shows nothing

My check engine light is on, the car ran out of battery and after jumping it, it is running kind of poorly, idling rough, etc. I plugged in the OBD-II scanner/reader, and it "has power" (green ...
2
votes
1answer
44 views

Detect engine stumble or hesitation

I want to know if I can detect my engine is having hesitation/stumble problem from an OBD. I mean not from any fault codes, but from the parameters obtained from the OBD. e.g. calculate the obtained ...
8
votes
1answer
65 views

Received frames from vehicles with multiple ECU chips

I'm not generally a 'car person', so hopefully I can explain this well enough to get some help here: When sending messages to an OBD-II device, I receive one response in most cars I've tested. ...
3
votes
0answers
58 views

BMW E90: Coming Home automatically on darkness

I have a BMW E90 ( pre- facelift ) with light package . Currently my car is set so that the " Coming Home " function can by pressing the headlight flasher is switched off, press at ignition . My ...
2
votes
2answers
4k views

Diagnosing “wrench icon” on 2010 Ford Fusion Hybrid: will OBD2 scanner help me?

On my 2010 Ford Fusion Hybrid, I frequently get the yellow "wrench" icon which appears on the LCD screen to the left of the speedometer. On approximately 25%-50% of the trips I take with the car, the ...
4
votes
2answers
112 views

Any open-source OBD scanner analysis tools?

I've been having some weird problems with my '06 Pontiac G6, and finally broke down and bought a Bosch code scanner to see if the DTCs could tell me anything... they didn't. This scanner has the ...