I bought an old 2004 Proton Gen2 car, and its Engine light is on, so I bought an OBD2 device to check the engine errors, but I can't manage to access to ECU.

Photo of engine light on:
enter image description here

photo of OBD device/port and when I connect it, the device light turns on. enter image description here I believe the socket is in good condition since the device light turns on.

Photo of Torque Pro android application: enter image description here

I checked the ECU box and everything seems alright. enter image description here

  • ECU seems working fine since Engine light is On.
  • OBD device working fine too, since app shows that it is connected to device.

so I'm not sure what is the problem.
also I'm new and don't have much experience and knowledge of maintaining car, so please do let me know if I'm doing anything wrong.

  • 1
    Are you sure that the device you purchased will work with your car? My car is VERY particular which devices it talks to...And if it dies not like one then it won’t...
    – Solar Mike
    May 1, 2018 at 12:55
  • 1
    "ECU seems working fine since Engine light is On." you can completely disconnect the ecu and that light will come on. I would check all fuses related to the ecu. I would try a different obd scan tool to see if can communicate.
    – Moab
    May 1, 2018 at 15:29
  • @SolarMike I see... I'm not exactly sure if the one that I bought is compatible with my car or not.
    – Bear
    May 2, 2018 at 4:49
  • @Moab how do I know which fuse is related to OBD? even I found them, how to check if the fuse is healthy?
    – Bear
    May 2, 2018 at 4:51
  • As far as I understand, Proton Gen2 ECU(before 2008) are 16 bit while ur ECU reader works with 32bits. that's why it cannot read your error log.
    – Amir
    Feb 4, 2020 at 5:41

1 Answer 1


When a scantool is unable to connect to a vehicles ECU:

  1. Make sure you have power to the OBDII connector under the dash. (Since the adapter lights up, it means you have power)

  2. Try connecting to a different OBDII compatible vehicle. If you can connect, it narrows the problem down to being between the scantool and vehicle.

  3. Try using a different scantool/adapter. There are many cheap OBDII adapters on the market that are just useless out of the box.

  • okay, I'll try that.
    – Bear
    May 2, 2018 at 4:51

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