I have got one stumping me here.
I was called to a shop to help with this 2010 Sebring. It has a P0755 code for a solenoid body. The customer had replaced the solenoid body, TIPM and PCM. I did the replace PCM process. The vehicle started, restarted and ran. We found that the TIPM would not energize the "key on power" to the PCM, Variable Force Solenoid or Solenoid Pack.
I have looked high and low to find what strategy the TIPM uses to determine when to energize the solenoid body. Does anybody know what the TIPM is looking for to energize the Solenoid Pack? This same power lead also goes to the line pressure sensor and the PCM. On the schematic there is not a normal relay controlling this. It is all solid state. There have been multiple TIPM modules and two PCM's tried here. Any ideas?
Have you scoped the current on the solenoid feed wire from pcm? It will turn on and shut off with in 500 ms If it detects a current issue in one of the solenoids. Clear the codes key on and watch the current. If it climbs briefly before pcm turns it off likely a solenoid or harness issue. If the pcm never turns it on I would check pcm power and grounds. I also manually actuate the solenoids
Robert, That is exactly what I needed to know. The shop said that they had checked the wiring against shorts and opens. I am now thinking there is too much load. I did notice on the scan tool there is a quick spike of the voltage when the key is switched on. The TIPM or PCM must be seeing too much load and shuts down. I will check this tomorrow when I go back. -Mike
Id probably try disconnecting S127(I think that's what it says in your diagram) and use a pp4 driver tester(in case it needs a resistance) from the tipm, after clearing the codes. If you have power, then I'd check for low resistance to ground(short) at the rest of the wires at that same splice pack. Hope this helps.
The info for when the TIPM energizes the transmission control output is found at the following locations: In Alldata follow this path: - Vehicle - Powertrain Management - Transmission Control Systems - Transmission Control System Relay - Transmission Control System Relay - Operation In Identifix search "transmission control relay", then scroll down to Description and Operation.
pretty good answers so far, don't forget those "made-up" diagrams leave out connectors, Check the OE diagrams as you may have a voltage drop affecting current flow.
UPDATE: Worked on this car today. Cut the wire at the TIPM and powered up the Yellow and Orange wire manually. Could see the Pressure control solenoid firing on the scope. Inrush current just over 2 Amps. Once stabilized around 1 1/2 Amps. Connected a relay inline to test. Still dropped voltage to near zero. Used a decade box to test when the voltage drops. It drops at 300 Ohms. The output from
UPDATE … Worked overnight on Monday building a solid state relay. The idea was to reduce the load on the sick TIPM to see what would happen. We were able to run the vehicle without generating codes. The current flow remained under 1.5 Amps, The 5 Amp Transistor never even got hot. At one point we were able to do a quick learn. When we were the fans stopped running for one key cycle…