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Questions tagged [obd-ii]

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).

6
votes
2answers
2k views

Is it possible to access multiple CAN buses through the OBD-II port?

As usual I apologize if this has been asked and answered somewhere. I try to only ask questions if I can't find an answer or a satisfactory answer. From my understanding the OBD-II port on vehicles ...
3
votes
1answer
298 views

Can we determine the Cleaning Requirement of Air Filter Using OBD

Many a times, the dealer guy says that the unclean air filter consumes more fuel as compared to clean. So, my question is, is this really related to air filter? If yes, can we determine the case using ...
7
votes
1answer
13k views

Is Torque App reliable to read O2 sensor data?

My 2006 Toyota Prius is throwing code P0420 and I used a cheap OBD-II reader with Torque App on Android to check if my O2 sensors are working or not. I tried the maintenance mode to just run the ...
2
votes
2answers
1k views

BMW E90: Professional Radio (Alpine CD73) USB Adapter won't work

I bought an USB Adapter which emulates a CD Charger. The port wasn't used yet. When I plugged my battery the Radio worked, but I couldn't find the CD charger /USB in my radio source menu. Do I have to ...
3
votes
2answers
641 views

Calculate current drain from the battery in a drive

Control module voltage is one of the OBD PID. It signifies the car battery voltage. Is there any way to calculate how much current is drawn in a drive (say 7 km from my office to home). The voltage ...
6
votes
1answer
7k 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 ...
4
votes
1answer
1k 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 ...
3
votes
1answer
951 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 ...
28
votes
2answers
40k 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
574 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 "...
4
votes
3answers
1k 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 ...
8
votes
4answers
13k 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
2answers
3k 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
349 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 ...
9
votes
1answer
3k 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 ...
2
votes
3answers
580 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 ...
17
votes
3answers
46k 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
1answer
756 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
911 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 ...
3
votes
0answers
527 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? http://www.ebay.in/itm/SuperMini-ELM-327-Bluetooth-v2-...
10
votes
2answers
665 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? ...
2
votes
0answers
91 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 | +------+-----+------...
6
votes
2answers
811 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'...
3
votes
2answers
1k views

Gear ratio from speed and rpm

https://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
160 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 ...
8
votes
4answers
11k 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 42)...
13
votes
1answer
4k 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-...
8
votes
1answer
5k 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 ...
2
votes
1answer
66 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 ...
2
votes
1answer
171 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
784 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 ...
2
votes
3answers
802 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 ...
2
votes
1answer
827 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)) /...
5
votes
2answers
5k 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 ...
2
votes
1answer
6k 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
2k 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 ...
4
votes
1answer
133 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 ...
6
votes
2answers
53k 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 will be ...
2
votes
1answer
130 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 ...
10
votes
2answers
3k 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. ...
2
votes
2answers
2k 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 ...
4
votes
0answers
192 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 ...
4
votes
1answer
541 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 ...
1
vote
1answer
103 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? ...
6
votes
2answers
7k 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 ...
2
votes
1answer
4k 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'...
2
votes
1answer
108 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 ...
2
votes
1answer
8k 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 ...
3
votes
1answer
158 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
2answers
5k views

Interpreting ABS/DSC fault code

I have an ABS, DSC and handbrake warning light (the latter telling me it's likely from one of the rear wheels) on my BMW E46 320d from 2001. The warning used to be intermittent (it would go away, then ...