Thread: code wizards, help with some coding? (OBDII diagnostic codes)

So how do I parse this:

Code:

>03
00E 
0: 43 06 01 00 02 00 
1: 03 00 C1 00 82 00 43 
2: 00 00 00 00 00 00 00 
43 01 01 01 
43 00 
>

At a guess it seems that lines prefixed with 'number:' could just have the "number:" prefix flensed, and catenate those lines together, then just treat them like really long lines. That being the case, what's the 00E line? It seems that no matter how I count, I can't make the number of numbers there add up to fourteen, unless a bunch of zeros at the end there are padding.

Gary (-;

Well, except for the bit where I don't know what to do with the "00E" on a line on its own:
Original data:

Code:

>03
00E 
0: 43 06 01 00 02 00 
1: 03 00 C1 00 82 00 43 
2: 00 00 00 00 00 00 00 
43 01 01 01 
43 00 
>

obdgpslogger output:

Code:

chunky@chunkppc:~/src/obdgpslogger/build$ ../bin/obdgpslogger -ps /dev/ttyUSB*
Opening serial port /dev/ttyUSB1, this can take a while
Successfully connected to serial port. Will log obd data
Your OBD Device claims to support PIDs:
PID: [column] human_name
00: [unknown] PIDs supported 00-20
01: [unknown] Monitor status since DTCs cleared
02: [dtcfrzf] DTC that caused required freeze frame data storage
03: [fuelsys] Fuel system 1 and 2 status
04: [load_pct] Calculated LOAD Value
05: [temp] Engine Coolant Temperature
06: [shrtft13] Short Term Fuel Trim - Bank 1,3
07: [longft13] Long Term Fuel Trim - Bank 1,3
0C: [rpm] Engine RPM
0D: [vss] Vehicle Speed Sensor
0F: [iat] Intake Air Temperature
10: [maf] Air Flow Rate from Mass Air Flow Sensor
13: [o2sloc] Location of Oxygen Sensors
14: [o2s11] Bank 1 - Sensor 1/Bank 1 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim
1C: [obdsup] OBD requirements to which vehicle is designed
1F: [runtm] Time Since Engine Start
20: [unknown] PIDs supported 21-40
21: [mil_dist] Distance Travelled While MIL is Activated
2F: [fli] Fuel Level Input
33: [baro] Barometric Pressure
40: [unknown] PIDs supported 41-60
42: [vpwr] Control module voltage
46: [aat] Ambient air temperature

6 trouble codes set [MIL is on]
Couldn't parse line for 03 00: 00E 
Error: P0601
Error: P0002
Error: P0003
Error: P00C1
Error: P0082
Error: P0043
chunky@chunkppc:~/src/obdgpslogger/build$

Oh, great mp3car forum OBDII wizards; does that look correct?

Gary (-;

Originally Posted by chunkyks

So how do I parse this:

Code:

>03
00E 
0: 43 06 01 00 02 00 
1: 03 00 C1 00 82 00 43 
2: 00 00 00 00 00 00 00 
43 01 01 01 
43 00 
>

At a guess it seems that lines prefixed with 'number:' could just have the "number:" prefix flensed, and catenate those lines together, then just treat them like really long lines. That being the case, what's the 00E line? It seems that no matter how I count, I can't make the number of numbers there add up to fourteen, unless a bunch of zeros at the end there are padding.

Gary (-;

Thats an elm327 isn't it

I think the response got a little garbled-how did you parse it? If i'm reading that right theres 3 1/2 responses there. Not sure bout the first half the 00E. The rest is 3 seperate responses each response is going to be the mode+0x40 so:

1) response to mode 3, 6 DTCs....P100,P200,P300,U100,B200,C300.
2) response to mode 3, 1 DTC......P101
3) response to mode 3, 0 DTCs

Originally Posted by chunkyks

Oh, great mp3car forum OBDII wizards; does that look correct?

Your off by a digit

For now my code is ignoring multiple ECUs.

That's my OBDPro plugged into an OzenElektronik 1610

So... when parsing responses... the first number *after* the mode+0x40 is the number of ECUs set?

Code:

2F: [fli] Fuel Level Input
33: [baro] Barometric Pressure
40: [unknown] PIDs supported 41-60
42: [vpwr] Control module voltage
46: [aat] Ambient air temperature

6 trouble codes set [MIL is on]
Couldn't parse line for 03 00: 00E 
Error: P0100
Error: P0200
Error: P0300
Error: U0100
Error: B0200
Error: C0300
chunky@chunkppc:~/src/obdgpslogger/build$

Better...

Gary (-;

Originally Posted by chunkyks

For now my code is ignoring multiple ECUs.

That's my OBDPro plugged into an OzenElektronik 1610

So... when parsing responses... the first number *after* the mode+0x40 is the number of ECUs set?

Code:

2F: [fli] Fuel Level Input
33: [baro] Barometric Pressure
40: [unknown] PIDs supported 41-60
42: [vpwr] Control module voltage
46: [aat] Ambient air temperature

6 trouble codes set [MIL is on]
Couldn't parse line for 03 00: 00E 
Error: P0100
Error: P0200
Error: P0300
Error: U0100
Error: B0200
Error: C0300
chunky@chunkppc:~/src/obdgpslogger/build$

Better...

Gary (-;

Yea which is elm327 based...elms tend to truncate null bytes...so in the future if you have an odd number in the response you can pad the beginning of the line with a 0.

Anyway, yea thats right now. Only thing is syntax (sorry) code+0x40 is the acknowledge, ECU->engine control unit (what your talking to), DTC->Diagnostic trouble code (the codes your getting back).

and I would say theres 2-3 ECU's responding

The first response could be limited by obd spec and be truncated to two messages although I suspect michbound was correct.

The second and third responses could easily have been combined into a single message and there is no reason why a controller would send DTC's and then a empty frame-so that is clearly two different ECU's.