Archived ESS help

[edgeman]

the other day my trucks(1995 5 speed) tach, speeedo,and the batteries wont charge. I cleaned the sensor and didnt help a bit. so now im thinking it is the sensor. just yesterday i orde the new sensor and proceded to take the old one off (didnt need it anyway right). after i took it off i headed to town for class and what do you know my speedo works now. now i have doubt if the ESS is bad and am wondering why the speedometer started working again. what i am asking is, is the ESS rally bad or do i have other problems. any help would be great.

 

[mfburns]

Are'nt you concerned that the batteries won't charge? If the voltage is low that may mess up the electrical, (what is an ESS), speed sensor. Do you have any trouble starting the engine? What is the battery voltage? I believe fully charged batteries should read about 12. 9~13V. I would loook at the charging issue first and then see what happens.

 

[edgeman]

the ess is the engine speed sensor. it senses the tach and if it is bad the truck will not charge. if the it senses the engine not running why charge the batteries. i know why the truck wont charge i am trying to find out is why the speedo started working after i unpluged the bad ESS. the truck starts fine and i do not drive it it is sitting at home. the batteries are new so the voltage is fine and i checked them. i am trying to assure myself that the ESS is my problem not somthing else, i can only drive the vehicle i am driving for so long.

 

[Joe G.]

The speedo works off a sensor on the transmission not the engine.

 

[edgeman]

ya i knew that but why would the speedo start working after i unplug the ESS. it tells me that there might be something else wrong. im just not sure.

 

[Joe G.]

The PCM may react differently to the ESS signal if it is an open circuit rather than weak or shorted or whatever.

 

[Missouri Mule]

edgeman, try to get the code(s) either by the Key method or scanner (code reader).

Don't know why the vehicle speed sensor would start working after you unplugged the ESS.

The PCM uses data from the ESS,VSS, and TPS to determine when to shift the auto trans into and out of overdrive.

The ESS sends data to the PCM which sends a signal to tach, the ESS signal is used for input (activate) ASD relay (which sends the PCM (EVR) line voltage, it has something to do with the AC also.

 

[edgeman]

hey just wanted to say that i swapped my dad ESS from his truck to mine and when i put his on mine the tach worked and it was charging, everything was back to normal so that my prob was the ESS. i was freaked out because i only had somuch time with the vehicle i was driveing. anyways thank you for all the help it is greatly appreciated.