1994 Pontiac Grand Prix

KENNETH001

MEMBER
1994 PONTIAC GRAND PRIX

1994 Pontiac Grand Prix

just bought a Grand Prix GTP, I believe it is having issues with the ECM, or so what I am told. I am sure that the speedometer is off, for example when I am going 60, it says I am going 80. Also, when I first take off, the cars temperature gauge will tell me it is overheating but I don't believe it is, so I pull over and shut it off and turn it right back on and the gauge goes back to normal. My blinkers are also having some issues, when I turn them on they will stay lit instead of blink but when they do get enough power to blink, my speedometer needle goes crazy. I was just wondering what is causing this? And if it is the ECM that needs to be replaced?

1 Reply

LEGITIMATE007

MECHANIC
5,121 POSTS

There are several things that you should check. Before you just go and change the ecm, for instance, your vehicle speed sensor could be causing the speedometer to go crazy, and the coolant temperature sensor could be causing the temp gauge to read high.(Check thermostat too). Also your flasher fuse could be causing your blinkers to act wierd, these are things that probably werent addressed a time ago and they just started building up. Now there are several things wrong, and they think they can wipe the problem out with a new computer. Could be the case but I doubt it. Check those things out. Computer is last resort