Obd2 only works with engine running?
So i noticed the obd2 on my 2004 gmc sierra has power, but the scanner won't connect to it with the ignition on. But with the engine running, it connects just fine with no trouble codes. Why is this?
So i noticed the obd2 on my 2004 gmc sierra has power, but the scanner won't connect to it with the ignition on. But with the engine running, it connects just fine with no trouble codes. Why is this?
military supporter
Because it is designed to read the active codes which are generated when the engine is running.
Andy C
No. On, not running.
Anonymous
It is probably a cheapo scanner. Get a decent one. As they always say, you get what you pay for. If it is not a cheapo scanner, it is broken. Do not overthink it.
thebax2006
It's usually a POS after market code reader. Go to Advance Auto or Auto Zone and try their code reader to see what happens.