So the transmission computer isn't getting the speed signal or the turbine speed signal aka input shaft speed?Or is it getting it and he just thinks it's not doing anything with it?I have seen a few of those computer's fail but usually the one's I have seen that people thought were bad was just a pressure issue valve body issue or a bad seal in the transmission. When I asked about the pressure I wasn't talking about the wheel spinning on the rack.I was asking if he actual hooked up a transmission pressure gauge and performed a pressure test on the fluid pressure in the transmission and the control of it?Here is the code description for the no 4th gear code P0734. Also below that is the pressure test I was asking about and i'm posting the pressure chart for it. For the no fourth gear code that could be pressure issue electrical issue seal failure etc.
The Transmission Control Module (TCM) calculates gear ratio based on the transaxle input and output speeds. The TCM compares the known gear ratio to the calculated ratio for the selected range. When the TCM detects an unknown gear ratio when 4th gear is commanded, then the DTC P0734 sets. DTC P0734 is a type C DTC.
* Engine is running
* TPS greater than 8%
* Trans fluid temperature between 21 C (70 F) and 130 C (266 F)
* Engine torque greater than 2 ft-lbs
* Commanded ratio = 1st gear
* No TPS, TFP, VSS, ISS codes
* No engine torque default
* Time since last manual range change greater than 6 seconds
* TFP not in PARK or NEUTRAL
* Vehicle speed greater than 5 km/h (3 mph )
* Check for improper transaxle operation per the chart.
* Check for an incorrect calibration.
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Tuesday, January 25th, 2011 AT 8:19 PM