prob w/auto shifting, any ideas

jkretzer

jkretzer

MegaCrank
Joined
Jul 9, 2006
Messages
1,444
this am i picked up my trailer and headed to do some work in my dodge, i havent driven it in 3 weeks but it ran fine then. anyway driving along with OD locked out at around 20mph the motor lugged down and i pretty sure it shifted into overdrive and locked, i lifted off the pedal, pushed the OD lock out button again and kept driving, it did it again and the check gauges light came on and then it went off, shifted odd again, then my fuel gauge went to nothing. i stopped at a stop sign and it shifted into od and locked at the stop sign and stalled the engine. i started it and locked it in 2nd and drove home. any ideas. could the tps cause this issue? it shifted through the gears fine for the first 5 miles or so, then f'd up. any help is greatly apprecaited. thanks
 
i drove it to a pull at the beginning of the month and it ran fine, i parked it and got in it this past fri and that is when it gave me a fit, still at a loss. going to make some calls tom to see if someone has an idea.
 
had a friend come down with a snap on solus pro scanner and it wouldnt communicate with the pcm, none of the sensors would register. found a used pcm at a junk yard out of the yard truck they were running around. hopefully it solves this prob.
 
installed the used pcm and had the same issues, nothing changed so there has got to be another reason why the pcm isnt communicating. i started cleaning grounds tonight, started at the bat terminals, then moved to the pass side cable bolted to the block. i know there is one behind the starter. are there any more grounds i need to pay attention to? i am also goign to swap out the crank sensor. does anyone have any thoughts? sypmtoms are no guages, odometer flashes on and off, trans relay buzzes constantly.
 
Sounds like the crank sensor is shorting out and making the PCM do weird things. I'd carefully check the wires to the crank sensor and follow them back as far as you can, on my 98, the crank sensor wires were shorting out on the intake plate and since it's a painted surface (sometimes grounding out, sometimes not), it was an annoying intermittent problem. On my truck, the tranny, AC, and alternator would still work normally; the short would kill the ABS, Airbag, Fuel Level, Coolant Temp, Odometer, and Speedo.

Another possibility is the overdrive solenoid is shorted out and somehow causing the PCM to freak out and not communicate. I think I would try unplugging the transmission harness and seeing if the scanner will communicate with the pcm.
 
i will check into what you mentioned tonight, i really appreciate the response. if the trans relay was pulled woul dthat isolate the pcm side and then scanned? if so he did this and mentioned somethign about trying to read just the pcm side of the system and that is when it connected and displayed all sensors as N/A. where is the OD solenoid? thanks josh
 
OD solenoid is in the Valve body.

If i remember right pin 6 on the connector is the ground side of the OD solenoid(pin 1 being 12v constant).
 
what is the best way to test the OD solenoid? i dont mnind taking it out, just want to test it before i purchase one.
 
Run a switch from the connector into the cab...to eliminate the computer. Should tell you if it's the computer (which you have ruled out anyway) or the solenoid.
 
You must log in or register to reply here.
Back
Top