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
votes
2answers
588 views

Writing CAN Messages

I want to know what should I write with the CAN ID to send it to ECU. I am using ELM327 and Raspberry Pi with all connections to OBD-II. Initially for sending general PIDs to the ECU through ELM327 ...
18
votes
3answers
640 views

What are good features to look for in an OBD-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 OBD-II reader to be able to find out for ...
7
votes
3answers
684 views

Calculating MPG from MAP sensor (or converting MAP data to MAF data)

My 2002 Honda Accord V6 has a Manifold Absolute Pressure sensor (MAP). I understand that this sensor gives out information in pressure units (psi or equivalent). After doing a bit of research, I ...
2
votes
0answers
2k views

Fuel Consumption and other Fuel related data from basic OBD-II parameters [duplicate]

I want to know how can i obtain the values of Fuel Consumption, Fuel Economy and other fuel related information from basic OBD-II parameters like Vehicle Speed, RPM, TPS etc. I have noticed that not ...
4
votes
1answer
158 views

Quick Oil Change place overfilled my BMW Z3

Just got this car, a BMW Z3 3.0 from a Tampa dealer and have not even had it 10 days and Check Engine Light came on. I wanted to get the oil changed to full synthetic just in case it wasn't and ...
15
votes
1answer
2k views

How do I find the correct pins in a CAN-BUS connector?

This question might be too technical for this forum, but I'll give it a go. I have a 2012 BMW R1200R motorcycle with CAN-BUS. I'd like to make an Arduino interface to the connector on the bike, but I ...
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?
6
votes
1answer
324 views

OBD2 and CAN-bus

Do all vehicles with OBD2 have a CAN-bus? Otherwise, what are the alternative buses used? Are there special versions of the buses for trucks and school-buses than for cars/suv/vans?
7
votes
1answer
89 views

Erratic single fault code: P0420, P0440, P0446. Normal variance, or indicative of something deeper?

Working on diagnosing an evap/emission/fuel system problem on my Toyota 2003 Corolla. More on that in this question. On 3/2, I saw a mechanic use his handheld OBD to read a code P0420. On 3/12, ...
5
votes
2answers
953 views

Reading OBD2 too fast

I'm writing a software to make a telemetry application for my 2001 VW Golf mk4 reading parameters from OBD2 using an ELM327 compatible cable. I succeeded so far. The problem that I have now, is that ...
4
votes
1answer
74 views

What is SAE 0x15 Short Term Fuel Trim Bank 1 Sensor 2?

I was taking a look at a neighbor's car, and noticed this PID stuck at 99.22% This is in addition to the regular STFT PID 0x06 which is staying fairly close to zero most of the time. What is this ...
3
votes
1answer
443 views

Oxygen sensor PID for 2004 Toyota Camry 4-cyl

My 2004 Toyota Camry with 170k miles is pulling a P0420 code, which I've read can be due to a bad catalytic converter or O2 sensors. I have an OBD-II tool with the DashCommand app on my iPhone. ...
3
votes
3answers
5k views

What should I do about PS0128 “Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)” error code?

I have a Mazda 6 and recently purchased the OBD 2 module and saw the check engine light with the PS0128 Error Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature). I ...
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)) /...
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 ...
1
vote
1answer
948 views

Reading CAN messages through UART to OBD-II Board and MATLAB Toolbox

I want to read/write CAN messages. I have MATLAB in my laptop which has a Vehicle Network Toolbox which supports reading/writing CAN messages. I have my hardware OBD-II to UART board, FTDI and OBD-ii ...
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 ...