Thread: a few things

I'm always slightly afraid when things are inconsistent.

That "-p" output looks right when it did work. Could you try creating a serial log a few times [--serial-log <file>], and see what you get when it works, and when it doesn't?

What exactly is the device that you have? I've never tested with anything that wasn't an ELM327. I've also never seen anything create a /dev/ttyACM device before. Where did you get it from?

My actual suspicion is that it's just a cheap chinese device that may just be not-entirely-functional [which wouldn't be unprecedented]. Are you able to open it and look inside? How is the main chip inside labelled? Does the circuit board look like it's properly soldered?

Thanks,
Gary (-;

The device was purchased from a european company called Secons. It is nicely soldered and seems to be well constructed, though the plastic housing is stamped "Made in China", as you guessed . The main chip is a PIC18F2455.

Here are 5 trials in a row. The command line, output and --serial-log output for each trial:

--------------------------------------------
1) doesn't work:
$ obdgpslogger -p --serial-log new.txt -s /dev/ttyACM0
Opening serial port /dev/ttyACM0, 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
Couldn't get obd bytes for cmd 00
00: [unknown] PIDs supported 00-20

ATZ^MATZ
ELM327/ELM-USB v1.0 (c) SECONS Ltd.
>^M
?
>0100^MATE0^MBUSINIT: ...OK
41 00 BE 3D B8 10
>ATL0^MATE0
OK
>ATS0^MOK^M>0100^M?^M>ATZ

-----------------------------
2) does work:
$ obdgpslogger -p --serial-log new.txt -s /dev/ttyACM0
Opening serial port /dev/ttyACM0, 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: [dtc_cnt] Monitor status since DTCs cleared
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
0B: [map] Intake Manifold Absolute Pressure
0C: [rpm] Engine RPM
0D: [vss] Vehicle Speed Sensor
0E: [sparkadv] Ignition Timing Advance for #1 Cylinder
10: [maf] Air Flow Rate from Mass Air Flow Sensor
11: [throttlepos] Absolute Throttle Position
13: [o2sloc] Location of Oxygen Sensors
14: [o2s11] Bank 1 - Sensor 1/Bank 1 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim
15: [o2s12] Bank 1 - Sensor 2/Bank 1 - Sensor 2 Oxygen Sensor Output Voltage / Short Term Fuel Trim
1C: [obdsup] OBD requirements to which vehicle is designed

ATZ^M>?^M>^M?^M>0100^M41 00 BE 3D B8 10^M>ATE0^MOK^M>ATL0^MOK^M>ATS0^M?^M>0100^M^M41 00 BE 3D B8 10^M>ATZ

------------------------------------
3) doesn't work:
$ obdgpslogger -p --serial-log new.txt -s /dev/ttyACM0
Opening serial port /dev/ttyACM0, 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
Couldn't get obd bytes for cmd 00
00: [unknown] PIDs supported 00-20

ATZ^MATZ
ELM327/ELM-USB v1.0 (c) SECONS Ltd.
>^M
?
>0100^MATE0^MBUSINIT: ...OK
41 00 BE 3D B8 10
>ATL0^MATE0
OK
>ATS0^MOK^M>0100^M?^M>ATZ

-----------------------------------------
4) doesn't work:
$ obdgpslogger -p --serial-log new.txt -s /dev/ttyACM0
Opening serial port /dev/ttyACM0, 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
Couldn't get obd bytes for cmd 00
00: [unknown] PIDs supported 00-20

ATZ^M>^M?^M>0100^M?^M>ATE0^M41 00 BE 3D B8 10^M>ATL0^MOK^M>ATS0^MOK^M>0100^M?^M>ATZ

--------------------------------------
5) does work:
$ obdgpslogger -p --serial-log new.txt -s /dev/ttyACM0
Opening serial port /dev/ttyACM0, 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: [dtc_cnt] Monitor status since DTCs cleared
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
0B: [map] Intake Manifold Absolute Pressure
0C: [rpm] Engine RPM
0D: [vss] Vehicle Speed Sensor
0E: [sparkadv] Ignition Timing Advance for #1 Cylinder
10: [maf] Air Flow Rate from Mass Air Flow Sensor
11: [throttlepos] Absolute Throttle Position
13: [o2sloc] Location of Oxygen Sensors
14: [o2s11] Bank 1 - Sensor 1/Bank 1 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim
15: [o2s12] Bank 1 - Sensor 2/Bank 1 - Sensor 2 Oxygen Sensor Output Voltage / Short Term Fuel Trim
1C: [obdsup] OBD requirements to which vehicle is designed

ATZ^M>?^M>^M?^M>0100^M41 00 BE 3D B8 10^M>ATE0^MOK^M>ATL0^MOK^M>ATS0^M?^M>0100^M^M41 00 BE 3D B8 10^M>ATZ