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 while watching a scope pattern of the current to try and spot a shorted or open solenoid coil. They have to be manually tested with jumper leads because the module will not control them when there are circuit codes
I have had to go through multiple pcms in those sebrings to get a good one. Last one I did there was no oe availability so we were relying on a rebuilder that sent 4 bad ones.
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.
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:
- 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.
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 TIPM is crap. This has been the case with 3 TIPM modules. All were used. Customer will not pony up for a new TIPM. I am working on some ideas tonight on how to address.
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. The trans temp started reporting correctly. Trans temp voltage is working like it should but the reported temp is -3 degrees. In studying the TIPM, there is only one power cable going in. There are multiple grounds all originating at the strut tower. All load tested OK. 250mV Drop from negative battery lug to engine assembly. All component activation is done from DATA coming in. With the fan issue, it seems that the modules report that they are on but I was not able to find any request. For instance: HVAC, Coolant Temp, Other DTCs. At this point we know that the TIPM is bad. It is strange that two used replacements have been crap. Why the low trans temp reading? Why the fans running?
If you ever need a solid state relay, I found this Hella model online: summitracing.com/parts/hla-h417… I don't know how reliable they are. Some reviews are good and some bad. It is an option where you need a low load to fire a device.
I added the LEDs to the SS relay so that I would no if our activities let the smoke out. We were lucky, it held up through 4 hours of testing.