The Transmission Control Module (TCM) for this transmission is a standalone controller mounted in a bracket to the side cover of the transmission assembly. The TCM has one 66 way connector to interface with vehicle electrical system, transmission assembly and other vehicle control modules. The TCM receives and sends various input and output signals from a number of switches and sensors within the transmission and throughout the vehicle. In addition, the TCM is part of a network of other control modules on the vehicle. This network of control modules will share information with each other, over a common serial data communications line. Based upon the TCM software/calibrations and input information the TCM receives, it will always have final authority of when to allow an upshift or downshift whether in manual mode operation or in drive position for automatic shifting. The TCM will command a 2-3 shift when the accelerator pedal position is below a certain calibrated value. When the pedal position is above this calibrated value, the TCM will command 2-4 shift.

The 9 speed transmission could contain a maximum of twelve individual solenoids – RPO dependent – installed in various bore locations on the lower control valve body assembly and transmission case. Eight of the twelve solenoid valves are used to control pressure regulation and direction of transmission fluid. The four ON/OFF solenoid valves are only used to direct transmission fluid.

The normal operating current range for these solenoid valves is between 0–1.2 amps. If the TCM detects an electrical circuit malfunction or excessive current flow, the TCM will turn OFF the high side driver to that solenoid and set a DTC. The high side driver will reset when the circuit fault is corrected and the ignition switch is cycled.

There are two slightly different designed variations of the pressure regulating solenoid valves used on this transmission. They are; linear variable force solenoid and normally low variable force solenoid.

Normally Low – Linear Solenoids

• A normally low linear solenoid actuator is an electro-mechanical device that converts electrical power into a mechanic pushing or pulling force or motion.
• When energized, the solenoid armature applies force to the face of a pressure regulating spool valve.
• The solenoid actuator applies minimum force with minimum current applied to the solenoid coil.
• The solenoid actuator applies maximum force with maximum current applied to the solenoid coil.
• Transmission control solenoid valves 1, 2, 5 and 6 are normally low.

Normally Low – Variable Force Solenoid

A normally low variable force solenoid is an electro-mechanically operated valve. The valve is controlled by an electric current through the solenoid coil.

• The solenoid valve varies the control pressure depending on the current applied to the solenoid coil.
• The solenoid valve control pressure is low with no or minimum current applied to the solenoid coil.
• The solenoid valve control pressure increases with increasing current applied to the solenoid coil.
• Nominal resistance of a variable force solenoid is 5.1 Ohms +/- .3 Ohms @ 20C (68F). As the temperature of the solenoid windings increase, the resistance will also increase. When the solenoid temperature is at 100C (212F), the resistance value will be approximately 6.7 Ohms +/- .4 Ohms.
• Transmission control solenoid valves 3, 4, and 8 are of the normally low design.

Normally High – Variable Force Solenoid

• A normally high variable force solenoid is an electro-mechanically operated valve. The valve is controlled by an electric current through the solenoid coil.
• The solenoid valve varies the control pressure depending on the current applied to the solenoid coil.
• The solenoid valve control pressure is high with no or minimum current applied to the solenoid coil.
• The solenoid valve control pressure decreases with increasing current applied to solenoid coil.
• Nominal resistance of a variable force solenoid is 5.1 Ohms +/- .3 Ohms @ 20C (68F). As the temperature of the solenoid windings increase, the resistance will also increase. When the solenoid temperature is at 100C (212F), the resistance value will be approximately 6.7 Ohms +/- .4 Ohms.
• Transmission control solenoid valve 7 is a normally high solenoid.

ON/OFF Solenoids

• The ON/OFF solenoid valve is an electro-mechanically operated valve. The valve is controlled by an electric current through the solenoid coil.
• This solenoid is normally closed solenoid that is controlled ON (fully open) or OFF (fully closed).
• Nominal resistance of an On/Off solenoid is 12.0 Ohms +/- .3 Ohms @ 20C (68F). As the temperature of the solenoid windings increase, the resistance will also increase. When the solenoid temperature is at 100C (212F), the resistance value will be approximately 15.8 Ohms +/- .4 Ohms. 
• Transmission control solenoid valves 9, 10, 11 & 12 are ON/OFF solenoids.

Solenoid Characterization

Transmission control solenoid valves 1–8 are pressure regulating valves. Each solenoid valve is tested after assembly to determine the output fluid pressure at certain electrical values, applied to the coil winding. This information is referred to as solenoid current/pressure data points. The solenoid valves are tested two ways, with an increasing and then a decreasing electrical current applied to the coil winding. The resultant current versus pressure data points are saved and assigned a file number. This file number is marked on the solenoid valve housing end or on the valve body itself. The solenoid performance data file is stored on the TIS web site. This data file is programmed and stored in the vehicle’s TCM. Replacing any of the following components will require the TCM to be programmed with either the new or existing solenoid valve performance data, depending on what component is replaced.

• Transmission assembly – program the TCM with the new data file stored on the TIS web site for all pressure regulating solenoid valves.
• Lower control valve body assembly with solenoid valves — program the TCM with the new data file stored on the TIS web site for all pressure regulating solenoid valves.
• Transmission Control Module — program the TCM with the existing data file stored on the TIS web site for all pressure regulating solenoid valves.
• One or more solenoids — program the TCM with the new data file stored on the TIS web site for all pressure regulating solenoid valves that were replaced.

The transmission fluid temperature sensor is a 2 wire negative temperature coefficient thermistor. The TCM supplies a 5 V signal circuit and a low reference circuit to the transmission fluid temperature sensor. The transmission fluid temperature sensor measures the temperature of the fluid in the transmission fluid pan. As the temperature of the fluid increase, the resistance of the sensor decreases, varying the voltage on the signal circuit. The transmission fluid sensor is part of the transmission internal wire harness assembly and has no serviceable parts. If the transmission fluid temperature sensor is faulty, then replace the internal transmission wire harness that has the sensor attached to it.

The input and intermediate speed sensors are housed together in one component assembly. The sensor is mounted on the exterior of the transmission case. Each sensor is triggered by a separate reluctor ring inside the transmission case. The input and intermediate speed sensors are both hall-effect type sensors. The TCM supplies a single 9 V reference circuit to power up both sensors. Each sensor has an independent signal circuit that returns to the TCM. The TCM uses the signals to determine the rotational speed of the input shaft and the reaction gear set. As the rotational speed of the reluctor wheel increases, the frequency of the speed signal increases. The transmission control module uses this information along with the output speed sensor signal to determine transmission line pressure, shift patterns, correct gear ratio and torque converter clutch slip speed.

• The input reluctor ring is part of the 5-7-R and 6-7-9 clutch subassembly.
• The intermediate reluctor ring is part of the 3-8 and 5-7-R clutch hub assembly.

The output speed sensor assembly is a two wire hall-effect type sensor. The sensor is mounted on the interior of the transmission case. The TCM supplies a 9 V reference circuit and signal circuit to the output speed sensor. As the rotational speed of the output carrier assembly increases, the frequency of the output speed sensor signal increases. The reluctor ring is part of the Park gear assembly, which is splined to the transmission output shaft. The TCM uses the output speed sensor signal along with the input and intermediate speed sensor signals to determine transmission line pressure, shift patterns, correct gear ratio and the torque converter clutch slip speed.

The transmission internal wire harness is serviced by replacement only. No repairs to the internal wire harness should be attempted.

The Transmission Fluid Pressure Accumulator Solenoid Valve is part of the Stop/Start system on the vehicle. The automatic transmission auxiliary fluid accumulator is used to supply transmission fluid line pressure to the appropriate clutches for an auto start event. Attached to the accumulator is a normally closed ON/OFF solenoid. When the ignition is ON, the engine control ignition relay supplies 12 V to the accumulator solenoid. To complete the circuit, the transmission control module (TCM) supplies a control circuit to the accumulator solenoid. When the engine control module (ECM) requests an auto start event, a serial data message is sent to the TCM, to command the solenoid ON. This allows captured pressurized fluid to exit the accumulator to apply the clutches for a 1st gear start.

The B303 Transmission Range Sensoris part of the Manual Shaft Detent Lever Assembly. The component is a hall-effect sensor that has two PWM output signal circuits (the sensor is able to provide a PWM due to the additional electronics located within the sensor). The engine control module (ECM) supplies a 5 V reference circuit and a low reference circuit. Sensor 1 signal circuit is an input to the TCM. Sensor 2 signal circuit is an input to the ECM. Each transmission gear range position has different duty cycle values of the PWM signal. The TCM uses the information from sensor 1 signal to determine what transmission gear range the vehicle operator has selected and apply the clutches for that gear. The ECM uses the information from sensor 2 signal to determine if the transmission is in park or neutral to enable the starter motor for engine cranking.

The transmission range control valve switch is a linear hall effect sensor that changes current flow based on magnetic field position relative to the sensor. The transmission control module (TCM) supplies a 9 V reference circuit to the transmission range control valve switch. Sensor signal circuit is an input to the TCM. The sensor signal circuit toggles between 0.7V and 2.2V based on valve position.

The park inhibit solenoid actuator (PISA) is an actuator that when energized, will lock the park servo in the applied position, holding the parking pawl out of the park position.

The transmission park valve switch is a linear hall effect sensor that changes current flow based on magnetic field position relative to the sensor. The transmission control module (TCM) supplies a 9 V reference circuit to the transmission park valve switch. Sensor 1 signal circuit and sensor 2 signal circuits both toggle between 0.7V and 2.2V based on valve position. There are two sensors within the component to serve as a redundancy for safety.

The TCM receives information from the Engine Control Module (ECM) on the LIN Bus. The LIN bus is used as a redundant way to control shift commands from the range selector. The image below depicts the signal that is received by the TCM, from the ECM in a normally operating vehicle. For additional information on LIN Bus, refer to: Data Link Communications Description and Operation

Solenoids F and G are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. Line pressure is directed by the transmission range control valves to the park on hydraulic circuit, which is used to assist the park servo return spring in overcoming the park servo apply fluid. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.

• Solenoids D,E,G, and PISA are on. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves.
• Solenoid D shuttles the transmission range control valve 2, allowing line pressure to enter the reverse hydraulic circuit feeding the clutch selector valve. The clutch selector valve directs the reverse fluid to the SOWC Servo which holds the SOWC during reverse. Solenoid E directs line pressure to the 57R Clutch.

• Solenoids F,G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. If shifting from Park to Neutral, solenoids C and D are on for 350 ms or less which shuttles the transmission range control valves, applying the park servo which disengages the parking pawl.
• If shifting to neutral from reverse or drive, the PISA is held on and the mode valves are returned to their default positions. Hydraulically, the system is in a Park state at this time. However, because the PISA was held on during the shift from R/D to Neutral, the parking pawl remains disengaged.

• Solenoids C,D,F,G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission range control valve 1 to allow line pressure to enter the Feed 1 hydraulic circuit which applies the park servo, disengaging the parking pawl. Solenoid D shuttles the transmission range control valve 2, preventing Feed 1 fluid from entering the drive hydraulic circuit.

• Solenoids D, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid D shuttles transmission range control valve 1 which allows Feed 0 fluid to enter the Reverse hydraulic circuit which applies the park servo, disengaging the parking pawl. The clutch selector valve is shuttled to prevent reverse fluid from applying any clutches.

• Solenoids C,F,G,and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.

• Solenoids C,G,and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F allows line pressure to enter the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.

• Solenoids B,C,F,G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Solenoid B allows Drive fluid to enter the 29C hydraulic circuit, applying the 29C Clutch assembly.

• Solenoids C,F,G,and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C is PWM in order to create a pressure high enough to shuttle the transmission range control valve 1 and the 38C regulator valve. This allows Drive fluid to enter the clutch selector valve, which directs Drive fluid into the Drive 2 hydraulic circuit. The 38C Regulator valve directs Drive 2 fluid into the 38C hydraulic circuit applying the 38C Clutch assembly.
• The transmission control valve 1 allows line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.

• Solenoids C,D,F,G,and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Solenoid D is PWM in order to create a pressure high enough to shuttle the transmission range control valve 1 and 4th Clutch regulator valve. This allows Drive fluid to enter the clutch selector valve, which directs Drive fluid into the Drive 2 hydraulic circuit. The 4th Clutch Regulator valve directs Drive 2 fluid into the 4th Clutch hydraulic circuit applying the 4C Clutch assembly.

• Solenoids C,E,F,G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Drive 2 fluid enters the 57R Clutch Feed hydraulic circuit. Solenoid E allows 57R Clutch Feed to apply the 57RC Clutch Assembly.

• Solenoids C,G,H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Line pressure is now able to flow through Solenoid F into the 1 Rev/6789C Clutch Feed hydraulic circuit. 1 Rev/6789C Clutch Feed fluid is directed into 6789C Clutch hydraulic circuit by the Clutch Selector Valve, which applies the 6789C Clutch Assembly.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.

• Solenoids A,C,E,G,H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Line pressure is now able to flow through Solenoid F into the 1 Rev/6789C Clutch Feed hydraulic circuit. 1 Rev/6789C Clutch Feed fluid is directed into 6789C Clutch hydraulic circuit by the Clutch Selector Valve, which applies the 6789C Clutch Assembly.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. Solenoid A does not allow Drive fluid to enter the 123456C Feed hydraulic circuit.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.
• Drive 2 fluid enters the 57R Clutch Feed hydraulic circuit. Solenoid E allows 57R Clutch Feed to apply the 57RC Clutch Assembly.

• Solenoids A,C,G,H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Solenoid C is PWM in order to create a pressure high enough to shuttle the transmission range control valve 1 and the 38C regulator valve. This allows Drive fluid to enter the clutch selector valve, which directs Drive fluid into the Drive 2 hydraulic circuit. The 38C Regulator valve directs Drive 2 fluid into the 38C hydraulic circuit applying the 38C Clutch assembly. Solenoid A does not allow Drive fluid to enter the 123456C Feed hydraulic circuit.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.
• Line pressure is now able to flow through Solenoid F into the 1 Rev/6789C Clutch Feed hydraulic circuit. 1 Rev/6789C Clutch Feed fluid is directed into 6789C Clutch hydraulic circuit by the Clutch Selector Valve, which applies the 6789C Clutch Assembly.

• Solenoids A,B,C,G,H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. Solenoid A does not allow Drive fluid to enter the 123456C Feed hydraulic circuit.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.
• Solenoid B allows Drive fluid to enter the 29C hydraulic circuit, applying the 29C Clutch assembly.