What are the pulse generators for?

[EagleTalonTim]

If anyone knows what the pulse generators do on the A/T please let me know. I cannot find any information on these things except how to replace them.

 

[Morphius]

Input/ouput speed sensors

 

[EagleTalonTim]

Would you happen to know which one does what? I have read that the sensors that are used are for creating frequency pulses. I am trying to find some kind of documentation on how many splines are on the gears that the pulse sensors read. I know there are 2 pulse generators, one on the top of the tranny and one on the side. I can't figure out which one does what or detects input/output

 

[Defiant]

If the top one you're speaking of is the speedometer sensor, it cycles four times per revolution.

 

[TFFC]

Both are input signals, they send an on/off signal to the TCU, and then the TCU sends a output signal to the solenoids in the tranny. I just had pulse generator b go bad on me, I ohmed it out and it was bad. The transmissing would just switch gears back and forth, because it didn't know how fast the shafts were spinning

 

[Burnett03]

Both are input signals, they send an on/off signal to the TCU, and then the TCU sends a output signal to the solenoids in the tranny. I just had pulse generator b go bad on me, I ohmed it out and it was bad. The transmissing would just switch gears back and forth, because it didn't know how fast the shafts were spinning

Where are these located on a 97 gst? I am getting a pulse generator CEL and need to figure out why. Thanks

 

[TFFC]

I believe the 2g has 3 of them. 2 are on the top of the trans, one by the shift linkage, and the other by the engine. Then their is one on the back side of trans by the fender,(towards the rear of the car). their is a 10mm bolt that holds them in. on my 1g, one had a clear tube, I believe the rear, and one had a black tube covering the wires. If you can find the connector,(believe its on top towards the front of the trans with like 2 other connectors) you can ohm them out and see if they are bad. I can try and find you the spec for the 2g.

 

[Morphius]

Both are input signals, they send an on/off signal to the TCU, and then the TCU sends a output signal to the solenoids in the tranny. I just had pulse generator b go bad on me, I ohmed it out and it was bad. The transmissing would just switch gears back and forth, because it didn't know how fast the shafts were spinning

Why would they have 2 input speed sensors??

 

[Colt4G63 also]

Why would they have 2 input speed sensors??

You guys are confusing each other. He meant they're both inputs, in that they both send (input) data to the ECU.

Eg. "The ECU recieves input from the input speed sensor, the output speed sensor, and the shifter position sensor. It uses this data to extrapolate the appropriate output to send to the shift solenoids."

 

[Bluefire16]

Something is wrong with mine...my tranny was rebuilt and now apparently mine went bad? They replaced a transmission solenoid and a speed sensor but the car was still in limp mode (yes its an A/T) So im curious ### could be the reason it is in limp mode? Could one of these have died?

 

[Burnett03]

I believe the 2g has 3 of them. 2 are on the top of the trans, one by the shift linkage, and the other by the engine. Then their is one on the back side of trans by the fender,(towards the rear of the car). their is a 10mm bolt that holds them in. on my 1g, one had a clear tube, I believe the rear, and one had a black tube covering the wires. If you can find the connector,(believe its on top towards the front of the trans with like 2 other connectors) you can ohm them out and see if they are bad. I can try and find you the spec for the 2g.

Thanks, i found the specs in the FSM. The car is no longer throwing pulse generator codes, now it's throwing p1750 (solenoid code) But only after driving for a few miles. The VSS is not working, would this make the car go into limp mode tranny wise?

 

[Bluefire16]

Its possible.... but its funny i had that same code thrown so thats actually what i just had replaced, and now they think its my pulse generator(s).

 

[TFFC]

Yes, pulse generators will make your car go into limp mode. Ohm them out and find out if any of them are bad. BTW they are pricey. I paid $70 for both, because you can't just buy one with my dealers discount. They were reg, $110 for my 1g from Mitsubishi. Hope this helps

 

[Bluefire16]

Yea i actually jsut had them ohmd and everything is ok with them....we believe it is my tcu so trynig a diff one tomorrow hopefully my car is fixed (almost been in the shop for 2 weeks!)