Transmission control module

According to the manual an 03 doesn't have a separate TCU, it is integrated in the PCM, located next to the fuse box driver side (see diagram below) Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

There is no separate transmission control module in that car. It is part of the Power-train Control Module. To replace it requires programming a new PCM to match the car. What is the issue with the transmission that makes it act like a bad TCM?

P0700 is a flag code telling you that you need to use a higher end scan tool to read the actual transmission codes that are stored. Most of the simple code scanners won't do that, they only see the P0700 code.

DTC P1776: SOLENOID SWITCH VALVE LATCHED IN L-R POSITION
NOTE:For circuit reference, see CONNECTOR IDENTIFICATION and/or WIRING DIAGRAMS.

NOTE:Always perform TRANSMISSION VERIFICATION TEST VER-1 after repair is completed. Ensure PRE-DIAGNOSTIC CHECKS have been performed before proceeding with following procedure. See PRE-DIAGNOSTIC CHECKS.

Circuit Description
DTC P1776 will set if PCM senses L-R pressure switch closing while actuating TCC. With 2 unsuccessful attempts made to actuate TCC, DTC will set. At speeds above 45 MPH, EMCC is inhibited. Once speed falls below 45 MPH, transaxle will go into limp-in mode and MIL will illuminate.
Possible Cause
The following items may be area of concern:
Transmission control relay output circuit open.
L-R pressure switch sense circuit open.
L-R pressure switch sense circuit shorted to ground.
L-R pressure switch sense circuit shorted to voltage.
Faulty PCM.
DTC P0841 present.
Incorrect fluid level.
Intermittent wiring and connector problems.
Internal transaxle problem (solenoid switch valve stuck).
Diagnostic Procedure
Using scan tool, check for transaxle-related DTCs. If DTC P0841 is also present, see DTC P0841: L-R PRESSURE SWITCH CIRCUIT. If DTC P0841 is not present, go to next step.
Using scan tool, check STARTS SINCE SET counter for DTC P1776. If counter is set at 2 or less, go to next step. If counter is not set at 2 or less, go to step 11.
NOTE:Failure to remove starter relay can cause a NO RESPONSE FROM TCM condition.

Turn ignition off. Remove starter relay from power distribution center. See Fig. 7. This prevents vehicle from starting in gear. Install Transmission Simulator (8333). Turn ignition on. Using transmission simulator, turn pressure switch selector knob to L-R position. Using scan tool, observe L-R solenoid switch state while pressing pressure switch button. If pressure switch state changes from OPEN to CLOSED while pressing button, go to next step. If pressure switch state does not change from OPEN to CLOSED while pressing button, go to step 6.
Ensure transaxle is at normal operating temperature. Check transmission fluid level. See appropriate SERVICING article in AUTOMATIC TRANSMISSIONS. Fill if necessary, and repair cause of low fluid level. If fluid level is okay, go to next step.
Transaxle has an internal problem and must be replaced or repaired. See appropriate OVERHAUL article. If transaxle is to be repaired, inspect solenoid switch valve in valve body and replace if necessary. If no problems are found in valve body assembly, replace solenoid assembly. See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS.
NOTE:When testing circuits with a test light, ensure test light illuminates brightly. Compare test light brightness of circuits to brightness of test light when connected to direct battery voltage. If circuits do not illuminate with same brightness as direct battery voltage, circuit must be repaired.

Turn ignition switch to LOCK position. Remove transmission control relay from power distribution center. See Fig. 7. Disconnect solenoid assembly harness connector. Using fused jumper wire, jumper fused B+ circuit and transmission control relay output circuit together at transmission control relay connector. See WIRING DIAGRAMS. Using test light connected to ground, probe transmission control relay output circuit at solenoid assembly harness connector terminal No. 4. If test light illuminates brightly, remove test light and jumper wire, and go to next step. If test light does not illuminate brightly, repair open or high resistance in transmission control relay output circuit. If fuse is open, check for short to ground or excessive resistance in output circuit.
Turn ignition switch to LOCK position. Disconnect PCM harness connector C4. See Fig. 13. Measure resistance of L-R pressure switch sense circuit between solenoid assembly harness connector terminal No. 2 and PCM harness connector C4 terminal No. 29 using Miller Special Tool (8815). See WIRING DIAGRAMS. If resistance is greater than 5 ohms, repair open sense circuit. If resistance is 5 ohms or less, go to next step.
Measure resistance between ground and L-R pressure switch sense circuit at PCM harness connector C4 terminal No. 29 using Miller Special Tool (8815). If resistance is less than 5 ohms, repair sense circuit for short to ground. If resistance is 5 ohms or greater, go to next step.
Connect fused jumper wire between fused B+ circuit and transmission control relay output circuit together at transmission control relay connector. See WIRING DIAGRAMS. Turn ignition on. Measure voltage between ground and L-R pressure switch sense circuit at PCM harness connector C4 terminal No. 29 using Miller Special Tool (8815). If voltage is greater than.5 volt, repair sense circuit for short to voltage. If voltage is.5 volt or less, go to next step.
If no other potential causes for DTC P1776 remain, PCM is assumed to be faulty. Repair or replace as necessary. See POWERTRAIN CONTROL MODULE under REMOVAL & INSTALLATION.
Conditions necessary to set DTC are not present at this time. Check for transaxle starting out in 2nd gear and/or no TCC engagement. Using wiring diagram as a guide, inspect wiring and connectors associated with circuits in question. See WIRING DIAGRAMS. Wiggle wires while checking for shorted and open circuits. Repair as necessary. This DTC may also set if solenoid switch valve intermittently sticks in it's bore under extreme temperature conditions. Ask customer for additional information on conditions in which DTC was set. If circuits and components are okay, replace solenoid assembly. See REMOVAL & INSTALLATION in appropriate SERVICING article in AUTOMATIC TRANSMISSIONS.

The powertrain control module (PCM), runs the engine. It has nothing to do with limp-in mode. Why did you put in the two sensors? Did anything change after they were installed? With the mileage you have, it's possible there is some slippage taking place during upshifts. The transmission computer watches the two rpm readings from the two sensors. Based on the programmed-in final drive gear ratio, it knows how fast the tires should be turning for any engine speed. When they don't agree, the transmission computer puts the transmission into second gear so you can at least drive it to the shop.

Did you take it to a GM dealer or a Chrysler dealer? The Chrysler dealer will connect a hand-held computer that can read the volume of fluid it takes to apply the various clutches. An experienced tech can tell the condition of the transmission from those numbers. This can't be done at a GM dealership.

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