Hi everyone,
I took my 2014 CLA250 last week to change transmission fluid and differential fluid as maintenance service at 100k milage, but afterward the Check Engine Light came on with code P013504 : the heater for oxygen sensor 1 (cylinder bank 1) has an electrical fault. there is an internal fault. : current and stored
after that I took my car in again to replace the new oxygen sensor, but the light is came on even with new sensor.
has anyone else have any insight into this issue? The repair people said it might be the ECU but they are not sure. Everything runs fine with the car, I don't feel it runs differently even the mpg is the same. Any help is appreciated. thanks in advance.