Loud Bang From Transmission and AT Light Comes On And Off

[tommyboy8603]

Hi,

I recently started to have this problem about a week ago and cannot figure out what is causing this issue. While I’m driving in the city or on the highway, my car will feel like its choking and there is a loud bang like the transmission is not shifting properly and the AT light will come on then go off. It happens at random times . If i push on the gas pedal to get on the highway, it just wants to choke. Also when it does that, it stalled once on me and other times the RPM went down to 0 then back up. Can this be related to a bad sensor or an electrical issue? I was thinking about replacing the MAF Sensor, but I don't know if the problem is related to that. Much appreciate anybody’s help.

**** It's a 2010 Mazda 3 2.5L / 205,000 KM'S *****
**** Transmission has already been replaced once, Mechanic said it had around 30,000 KM's on it ****

[Pocky]

I think you should stop driving it or minimize driving it and take it to a mechanic. Don't want to risk damage.

[tommyboy8603]

I figured out the problem that was causing this. i got this code on my OBD Reader :


P0685 Mazda - Electronic Control Module Power Relay Control Circuit Malfunction

Possible causes
- Faulty Engine Control Module (ECM) power relay
- ECM power relay harness is open or shorted
- ECM power relay circuit poor electrical connection
- Faulty (ECM)

Tech notes
Check all the ECM fuses, if the fuses are OK try replacing the ECM relay.

P0685 Mazda Description
The Engine Control Module (ECM) has detected that the ECM remains powered up after the ignition key has been turned off

[greyseason]

Awesome reader