P2123 obd code

Question

I recently bought a new ECM for my Cadillac CTS 2005, it had the common gas gauge, temp gauge, traction control light problems so I bought the new ECM and it was supposedly programed to my vin at there shop and it was supposed to be ready to go, well I installed it and it fixed the gauge problems but I'm getting a p2123 code and even if i clear it it will come back immediately, my car runs better now but it won't accelerate, when I step on pedal it revs up to about 3500 rpm and then it will shift two 2nd and same thing for 3rd, I don't think I am hitting 4th cause I can only get up to about 60mph, also if I install the old ECM back in car the car accelerates fine but of course all the gauges and stuff don't work, DO you think it's a problem with the new ECM ,

Answer 1

That proof the ECM has the problem , this code condition fits the situation P2123 (APP sensor 1 circuit high) , circuit high means there is a open circuit.When the ECM is plugged in APP sensor 1 voltage should go to 1 volts, This can be the pin connection of the ECM, As for the old ECM , for the gauge problem check to see if the dealer will honor the Recall they had for the gauge problem. where they reprogram the ECM for the fault.