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
286 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 ...
3
votes
1answer
60 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
1k 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 ...
20
votes
2answers
1k 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?
4
votes
2answers
96 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 ...
2
votes
2answers
270 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 ...
2
votes
1answer
48 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
177 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
94 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 ...
7
votes
1answer
288 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 ...
10
votes
1answer
99 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? ...
12
votes
2answers
2k 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
3k 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
189 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
130 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
112 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 ...
6
votes
2answers
71 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 Power'...
2
votes
0answers
22 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
144 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 ...
6
votes
1answer
38 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
141 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
260 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
1k 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 ...
8
votes
1answer
367 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 ...
10
votes
1answer
585 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 car-...
1
vote
4answers
83 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?
2
votes
1answer
72 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
150 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 ...
9
votes
3answers
215k 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 ...
2
votes
3answers
144 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
1answer
326 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
122 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
190 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
417 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
101 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
57 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
103 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
48 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 ...
3
votes
0answers
81 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
5k 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
259 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 ...
1
vote
1answer
50 views

How can I tell if I would benefit from higher octane fuel?

Given the number of variables involved in whether an engine will knock on a given fuel in a given environment: How can an end user determine whether the engine is retarding timing due to fuel octane? ...
3
votes
1answer
4k views

What does error code: POO13 mean?

My vehicle: Saturn VUE 2008, 2WD 4Cylider. Checking light is steady on. Read code at auto zone store, POO13. The mileage is only 45K. I have no idea. Thanks for advice.
2
votes
1answer
421 views

Read error codes without scanner on Pontiac G6

I've read certain vehicles may begin flashing their check engine light if one bridges the diagnostic plug correctly with some wire before starting the vehicle. How does one do this for a Pontiac G6? I'...
1
vote
2answers
298 views

ECU signals to CAN bus

What methods or ideas are out there that can match or change an SR20det ECU's signals or codes in order for a newer CAN bus system to read, for example, the power steering to work as well as the ...
2
votes
2answers
977 views

Live scan tool for OBD 1.5 GM transitional?

1995 S-10 Blazer 4.3L Vortec V6 (vin W) with Powertrain Control Module (PCM) 1995 was the OBD transitional year for GM. The PCM itself is OBDI, but the interface connector has the 16-pin D-style ...
1
vote
1answer
2k views

OBD2 to USB Cable for Windows 10

One could put an argument that this question is about software and not mechanics, however now-days everything is computerized (including cars and their diagnostic tools) so I believe this question ...
2
votes
1answer
59 views

Do car manufacturers provide specific make/model/year information for each diagnostic-trouble-code?

Recently my car's check-engine light came on, I used a car OBDII port code reader to get the diagnostic-trouble-code (DTC) and then I googled what the DTC meant. I noticed that lots of the websites ...
3
votes
1answer
56 views

Is OBD-II a universal standard?

I'm following this guide: http://www.instructables.com/id/How-to-fix-your-check-engine-light/?ALLSTEPS According to this website an OBD-II reader will work with my 53 Vauxall Zafira, but I want to be ...
2
votes
1answer
2k views

Error MIL: off Spark ignition

I checked my OBD2 sensor and it shows on DTC that message. Along with P0171 system too lean on my Mazda 3. I put in an injen intake and that was 3 years ago. The check engine light came on 3 months ...