Hello,
First time poster- thanks to all you guys who answer questions and build out a reference for all the owners out there.
I have a question about troubleshooting auto trans shift issues. My father has an '04 DR 5.9 automatic that I work on for him when needed. I have replaced the pressure control solenoid and sensor in the trans a long time ago, so I didn't think too much of it when it started acting a bit goofy again. I replaced the pressure control solenoid and sensor and did the fluid/filter. All was well- for a little while. Now occasionally the upshifts are delayed, or it gets stuck in low gear. Sometimes it is fine. When it shifts while misbehaving, the mechanical shift seems to be OK- the shiftpoint vs. vehicle speed for a given throttle is just way wrong. For what it is worth, I replaced the TPS (out on the engine) a while back because of a DTC and an occasionally glitchy pedal off idle.
It would seem something is breaking down with the pressure control loop or the governor pressure and I need to do some more diagnosing. I thought, since the ECU is obviously reading the sensor and PWM'ing the solenoid, that I should be able to see these, but my little handheld OBD reader does not give me any information. Is there an inexpensive tool out there that would let me see/log the pressure target/setpoint, the sensor feedback, the solenoid control duty, or the solenoid current (if measured)? And as a side note, is there not a DTC when the pressure fails to be controlled?
And in case I am focusing on the wrong thing- more generally, what can help me narrow down the problem? Any advice is appreciated!
Thanks,
Tim
First time poster- thanks to all you guys who answer questions and build out a reference for all the owners out there.
I have a question about troubleshooting auto trans shift issues. My father has an '04 DR 5.9 automatic that I work on for him when needed. I have replaced the pressure control solenoid and sensor in the trans a long time ago, so I didn't think too much of it when it started acting a bit goofy again. I replaced the pressure control solenoid and sensor and did the fluid/filter. All was well- for a little while. Now occasionally the upshifts are delayed, or it gets stuck in low gear. Sometimes it is fine. When it shifts while misbehaving, the mechanical shift seems to be OK- the shiftpoint vs. vehicle speed for a given throttle is just way wrong. For what it is worth, I replaced the TPS (out on the engine) a while back because of a DTC and an occasionally glitchy pedal off idle.
It would seem something is breaking down with the pressure control loop or the governor pressure and I need to do some more diagnosing. I thought, since the ECU is obviously reading the sensor and PWM'ing the solenoid, that I should be able to see these, but my little handheld OBD reader does not give me any information. Is there an inexpensive tool out there that would let me see/log the pressure target/setpoint, the sensor feedback, the solenoid control duty, or the solenoid current (if measured)? And as a side note, is there not a DTC when the pressure fails to be controlled?
And in case I am focusing on the wrong thing- more generally, what can help me narrow down the problem? Any advice is appreciated!
Thanks,
Tim