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I am trying to read dtc codes using following procedure:

1 - send 0101 which means get the number of the dtc codes

receive - 41 01 82 07 61 01 which means I have 2 trouble codes

2 - send 0x03 to receive codes and

receive - 43 01 33 03 01 00 00 which are the 2 codes : P0133 and P0301

Using a diagnostic service tester I get 5 codes on the same car: P0133, P0301 (the ones I get also) and P0303, P0300 and C1513

How can I see the other 3 codes using my OBD?

Here are pictures with the tester:

dtc1

dtc2

starball
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lucian_v
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1 Answers1

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You might have multiple OBD2-conform ECUs in your car. To access these, use broadcast addressing or query each and every one separately by adjusting your arbitration ids.

That said, some readers may also show pending (0x07) or permanent (0x0A) DTCs.

DrMickeyLauer
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  • I did 07 and 0A but I am not sure I know how to decode the answer> 0x07 >>>47 01 33 03 01 03 03 > 0x0A >>>7F 0A 11 > any idea or some hint? – lucian_v Feb 11 '23 at 15:12
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    0133 0301 0303 are the _pending_ (not confirmed) DTC codes, which matches the output of your external tester. A result of `7F 0A 11` means 'Service 0A not supported'. (which is a bit strange, since this isn't an OBD2 answer, but a UDS one ­– OBD2-compliant ECUs should rather not answer at all to that service, but anyways). As for C1513, this comes from your ABS control unit, which ­– as I've answered ­– seems to be an OBD2-compliant ECU that is also answering to the tester's broadcast request. – DrMickeyLauer Feb 12 '23 at 17:37
  • thanks, I understand C1513 is from different ECU but why still I miss P0300 code? – lucian_v Feb 13 '23 at 07:07
  • No idea offhand. Would be interesting to see the actual data stream. Perhaps you can take another adapter, attach a multiplier cable, and log the communication between your car and the tester. – DrMickeyLauer Feb 13 '23 at 08:18
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    Some testers might display P0300 because more than one of P0301 .. P0306 is present. P0300 means that some cylinders misfired, P030n tells you which cylinders. – MSpiller Feb 13 '23 at 08:55