5.7 hemi PCM / gearbox issue ..thoughts please.

[holdens-recovery]

Hi My 2007 ram hemi has developed a fault with the gearbox, output speed sensor is out of range. anyway.. i put in a new sensor and plug.. still the same. ive done some diagnostic work, checked all the wiring up to the PCM, it now seems to me that the fault is in the PCM. The output speed sensor reading is reading very jumbled when looking at the live data.

Has anyone had this before ? I'm stuck in the U.K..and while i can get a PCM from a dealer here ( or rock auto ) no problem.. I was wondering if any one knows anywhere that can repair this fault ?

Ive found a few places in the USA that sell plug and play PCMs but im not very trusting of these sorts of places... usually just selling a junk yard PCM with some silver spray paint on !!

any suggestions or ideas on this one please.. thanks !

 

[jws123]

PCMs do not really fail that often its most likely something else never came across this issue myself Did you use a OEM sensor?

 

[holdens-recovery]

hi, no not an OEM sensor, however i swapped out for the front sensor which is the same sensor and the fault was exactly the same. I found a diagnostic check list from mopar who suggest all the tests ive done already. If they all pass then to replace the PCM. as described here.

P0720 Output Speed Sensor Error

P0720 OUTPUT SPEED SENSOR ERROR When Monitored and Set Condition: When Monitored: The transmission gear ratio is monitored continuously while the transmission is in gear. Set Condition: If there is an excessive change in output RPM in any gear. This DTC can take up to five minutes of problem iden...

mopar1973man.com