Question

2008 Chevrolet Impala 3.5L with engine code P0641 and car no start, traction control display on the dashboard

Answer 1

P0641 5 volt refference 1 circuit

This code condition is for a 5 volts refference known as circuit 1, circuit 1 along its Bus has more than 1 sensor that it gives a 5 volts reference to. The sensor for these on circuit 1 are : the MAP sensor, fuel tank pressure (FTP) sensor,the accelerator pedal position (APP) sensor 2 , the a/c pressure sensor,the cam position sensor, the throttle position sensor and the CKP (crank position sensor)  one sensor along this circuit or BUS can short out causing all the other sensor to be affected,

 

In this diagram the loss of the 5 volts refference to circuit 1 start by checking the fuse listed as ECM IGN  and swap out or replace relay listed as PWR/TRNS relay.,

Answer 2

P0641 CHEVROLET - 5 Volt Reference Voltage Incorrect

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