Engine/Transmission (1998.5 - 2002) Ecm

[blubyu]

Does the ECM have any thing to do with the charging system on a 2001 A/T? Oo.

 

[Bob4x4]

The pcm controls the charge rate... ... .....



Bob

 

[blubyu]

But wher does the pcm get its signal to tell the alt to charge?

 

[Bob4x4]

The charging system is turned on and off with the ignition switch. The system is on when the engine is running and the ASD relay is energized. When the ASD relay is on, voltage is supplied to the ASD relay sense circuit at the PCM. This voltage is connected through the PCM and supplied to one of the generator field terminals (Gen. Source +) at the back of the generator.



The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM. This circuitry is connected in series with the second rotor field terminal and ground.



A battery temperature sensor, located in the battery tray housing, is used to sense battery temperature. This temperature data, along with data from monitored line voltage, is used by the PCM to vary the battery charging rate. This is done by cycling the ground path to control the strength of the rotor magnetic field. The PCM then compensates and regulates generator current





Hope this helps

Bob

 

[blubyu]

ASD relay does not energize after the truck is running only when you turn the switch on, it will be on for a few seconds. Thanks for your help. Can not find the problem. It has no output from the alt. No signal going to the alt to tell it to charge.