Is there a sensor that controls automatic transmission shifting?

DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient
Probably plugged passage's , not the EGR valve .
What type code reader are you using to read these codes ? I have factory service info. Doesn't show P0842 or P0642 , no such codes . You don't show what engine yours has , I'am assuming you have 3.5 L !
P0604
Control Module Random Access Memory (RAM)
PCM
DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 in Engine Controls - 2.2L (L61)
or
DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 in Engine Controls - 3.5L (LX9)

P0717
Input Speed Sensor Circuit Low Voltage
PCM
DTC P0717 in Automatic Transaxle - 4T40-E/4T45-E
P0741
Torque Converter Clutch (TCC) System - Stuck Off
PCM
DTC P0741 in Automatic Transaxle - 4T40-E/4T45-E
P0742
Torque Converter Clutch (TCC) System - Stuck On
PCM
DTC P0742 in Automatic Transmission - 4T40-E/4T45-E
P0748
Pressure Control (PC) Solenoid Control Circuit
PCM
DTC P0748 in Automatic Transmission - 4T40-E/4T45-E
P0751
1-2 Shift Solenoid (SS) Valve Performance - No First or Fourth Gear
PCM
DTC P0751 in Automatic Transmission - 4T40-E/4T45-E
P0752
1-2 Shift Solenoid (SS) Valve Performance - No Second or Third Gear
PCM
DTC P0752 in Automatic Transmission - 4T40-E/4T45-E
P0753
1-2 Shift Solenoid (SS) Control Circuit
PCM
DTC P0753 in Automatic Transmission - 4T40-E/4T45-E
P0756
2-3 Shift Solenoid (SS) Valve Performance - No First or Second Gear
PCM
DTC P0756 in Automatic Transmission - 4T40-E/4T45-E
P0757
2-3 Shift Solenoid (SS) Valve Performance - No Third or Fourth Gear
PCM
DTC P0757 in Automatic Transmission - 4T40-E/4T45-E
P0758
2-3 Shift Solenoid (SS) Control Circuit
PCM
DTC P0758 in Automatic Transmission - 4T40-E/4T45-E
P0815
Upshift Switch Circuit
PCM
DTC P0815 in Automatic Transmission - 4T40-E/4T45-E
P0816
Downshift Switch Circuit
PCM
DTC P0816 in Automatic Transmission - 4T40-E/4T45-E
P0826
Up and Down Shift Switch Circuit
PCM
DTC P0826 in Automatic Transmission - 4T40-E/4T45-E
P0973
1-2 Shift Solenoid (SS) Control Circuit Low Voltage
PCM
DTC P0973 in Automatic Transmission - 4T40-E/4T45-E
P0974
1-2 Shift Solenoid (SS) Control Circuit High Voltage
PCM
DTC P0974 in Automatic Transmission - 4T40-E/4T45-E
P0976
2-3 Shift Solenoid (SS) Control Circuit Low Voltage
PCM
DTC P0976 in Automatic Transmission - 4T40-E/4T45-E
P0977
2-3 Shift Solenoid (SS) Control Circuit High Voltage
PCM
DTC P0977 in Automatic Transmission - 4T40-E/4T45-E

Sometimes with code readers they get confused an just throw any old codes . Have it checked by someone with GM Tech 2 scan tool .

Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
• The automatic transmission shift lock control solenoid
• The automatic transmission shift lock control switch
With the ignition in the ON position, voltage is supplied to automatic transmission shift lock control switch. Voltage flows through the normally closed contacts of the automatic transmission shift lock control switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid causing the transmission shift lever to be physically locked in the PARK position. When the brake pedal is pressed the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to be move out of the PARK position.

Circuit Description
The transmission range (TR) switch is part of the park/neutral position (PNP) and back-up lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The powertrain control module (PCM) supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.

These are all electronically controlled , yur best bet would be to take your vehicle to the dealer .

I would think it has something to do with
Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consist of the following components:
• The automatic transmission shift lock control solenoid.
• The automatic transmission park lock solenoid (Regal only).
• The automatic transmission shift lock control switch.
• The transmission range switch.

Regal
With the ignition in the ON position, battery positive voltage is supplied to the automatic transmission shift lock control switch. The circuit continues through the normally-closed switch to the automatic transmission shift lock control and park lock solenoids. The transmission range switch provides a path to ground in the PARK position. With the automatic transmission shift lock control and park lock solenoids energized the shift lever is locked in the PARK position. When the driver presses the brake pedal, the contacts in the automatic transmission shift lock control switch open. This causes the automatic transmission shift lock control and park lock solenoids to release. This allows the shift lever to move from the PARK position.
Do the brake lights work ? If not could be cause by bad brake light switch .

PRND321 Display
The instrument panel cluster (IPC) displays the selected gear position as determined by the engine control module (ECM). The IPC - instrument panel cluster receives a serial data message from the ECM indicating the gear position. The PRND321 display blanks if:
?€¢
The ECM detects a malfunction in the transmission range switch circuit.

?€¢
The IPC detects a loss of serial data communications with the ECM. The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
?€¢
The automatic transmission shift lock control solenoid

?€¢
The automatic transmission shift lock control switch

With the ignition in the ON position, voltage is supplied to automatic transmission shift lock control switch. Voltage flows through the normally closed contacts of the automatic transmission shift lock control switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid causing the transmission shift lever to be physically locked in the PARK position. When the brake pedal is pressed the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to be move out of the PARK position.
The transmission range (TR) switch is part of the park/neutral position (PNP) and backup lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The PCM supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.
You need a Tech2 scan tool to diagnose this problem ! possible range sensor !

Hi Judy , what kind of vehicle do you have ? Year an model ? ABS light has nothing to do with it not coming out of park . Problem with automatic transmission shift lock control ! Probably !
The automatic transmission shift lock control is a safety device that prevents an inadvertent shift out of PARK when the ignition is ON. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
?€¢
The automatic transmission shift lock control solenoid.

?€¢
The automatic transmission shift lock control switch.

?€¢
The park/neutral safety switch.

With the ignition in the ON position, battery positive voltage is supplied to the automatic transmission shift lock control switch. The circuit continues through the normally-closed switch to the automatic transmission shift lock control solenoid. The park/neutral safety switch provides a path to ground for the automatic transmission shift lock control solenoid in the PARK position. This energizes the automatic transmission shift lock control solenoid, mechanically locking the shift linkage in the PARK position. When the driver presses the brake pedal the contacts in the automatic transmission shift lock control switch open, causing the automatic transmission shift lock control solenoid to de-energize. This allows the shift lever to move from the PARK position. When the shift lever is out of the PARK position the contacts in the neutral safety switch open and the automatic transmission shift lock control solenoid is de-energized.

Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the ignition is ON. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
?€¢
The automatic transmission shift lock control solenoid

?€¢
The automatic transmission shift lock control switch

?€¢
The brake to shift relay

?€¢
The rear integration module (RIM)

With the ignition in the ON position, battery positive voltage is supplied to the brake to shift relay coil. When the RIM energizes the brake to shift relay, the brake to shift relay switch contacts close suppling battery voltage to the automatic transmission shift lock control switch. The circuit continues through the normally --closed switch to the automatic transmission shift lock control solenoid. The permanently grounded solenoid is energized. This locks the shift linkage in the PARK position. When the driver presses the brake pedal, the contacts in the automatic transmission shift lock control switch open. This causes the automatic transmission shift lock control solenoid to release. This allows the shift lever to move from the PARK position.
Shift Lever Does Not Move with Brake Pedal Depressed ?

Here is what the service manual says about the EPC solenoid, the processor looks at allot of different inputs to command the solenoids, such as Throttle Position Sensor, Vehicle Speed Sensors, Transmission Range Sensor and RPM signal, The PCM controls the shift patterns for the transmission. Electronic Pressure Control (EPC) Solenoid
The electronic pressure control (EPC) solenoid is located on the main control valve body and is controlled by the PCM. The EPC controls line pressure used to apply and release clutches and bands in the transmission.
The 2-3 shift solenoid is located on the main control valve body and is switched on and off by electrical signals from the PCM. The 2-3 shift solenoid activates the 2-3 shift valve which controls the automatic shifting between second and third gear. Second gear is established when the 2-3 shift solenoid is switched on. The 2-3 shift solenoid is switched off when vehicle speed increases and requires a second to third gear upshift.
The 3-4 shift solenoid is located on the main control valve body and is switched on and off by electrical signals from the PCM. The 3-4 shift solenoid activates the 3-4 shift valve which controls the automatic shifting between third and fourth gear. Third gear is established when the 3-4 solenoid is switched off. The 3-4 shift solenoid is switched on when vehicle speed increases and requires a third to fourth gear upshift.

Automatic Transmission Shift Lock Control Description and Operation
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of thew following components:
• The automatic transmission shift lock control solenoid
• The body control module (BCM)
• The powertrain control module (PCM)
With the ignition in the ON position, battery positive voltage is supplied to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid receives a ground from the BCM. When the automatic transmission shift lock control solenoid is energized, the shift lever mechanically locked in the PARK position. When the driver presses the brake pedal the PCM sends a class 2 serial data message to the BCM. The BCM turns OFF the ground control circuit and this de-energizes the automatic transmission shift lock control solenoid. When the automatic transmission shift lock control solenoid is de-energized, the shift lever may be moved out of the PARK position. The BCM determines transaxle shift lever position through a class 2 serial data message from the PCM. The PCM receives inputs from the park/neutral position switch and determines shift lever position. When the BCM receives this information and determines that the shift lever is out of the PARK position, the automatic transmission shift lock control solenoid ground is opened.

Do you know what a DTC is ? Diagnostic trouble code !

DTC B2708
The body control module (BCM) controls the automatic transmission shift lock control solenoid. Positive voltage is supplied via the ignition 1 voltage circuit to the automatic transmission shift lock control solenoid. The BCM controls the ground circuit of the automatic transmission shift lock control solenoid . When the brake pedal is depressed, the BCM removes the ground allowing the solenoid to disengage. This action allows the vehicle to be shifted out of the PARK position.
Conditions for Running the DTC
DTC B2707

Your best bet mite be to have a qualified repair shop check it .

Shift - interlock system problem .
Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of PARK position. The system consists of the following components:
• The automatic transmission shift lock control solenoid
• The automatic transmission park lock solenoid
• The automatic transmission shift lock control switch
• The transmission range switch
With the ignition in the ON position, battery voltage is supplied to the automatic transmission shift lock control switch. The circuit continues through the normally-closed switch to the automatic transmission shift lock control solenoid. The transmission range switch provides a path to ground for the automatic transmission shift lock control solenoid in the PARK position. With the automatic transmission shift lock control solenoid energized the shift lever is mechanically locked in the PARK position. When the driver presses the brake pedal, the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to move from the PARK position. When the shift lever is out of the PARK position the controlled ground contacts in the transmission range switch open. This prevents the automatic transmission shift lock solenoid from energizing when the vehicle is out of the PARK position.

Check Engine Light Codes and Meanings
Long blinks Short blinks Problem
1 1 Camshaft position sensor
1 2 Mass air flow sensor
1 3 Engine coolant temperature sensor
1 4 Speed sensor
1 11 EVAP control system (flow)
1 14 Fuel injection system right bank (too rich)
1 15 Fuel injection system right bank (too lean)
2 1 Ignition circuit
2 3 Closed throttle position switch
2 5 Idle speed control
2 9 Fuel Injection system left bank (too rich)
2 10 Fuel Injection system left bank (too lean)
3 1 ECU
3 2 Exhaust gas recirculation system flow problem
3 3 Front left O2 sensor
3 4 Knock sensor
3 5 Exhaust gas recirculation temperature sensor
3 6 EGRC-BPT valve
3 7 Closed loop control
3 8 Closed loop control
4 1 Air intake temperature sensor
4 2 Fuel tank temperature sensor
4 3 Throttle position sensor
4 7 Crankshaft position sensor
5 3 Front right O2 sensor
5 4 Automatic transmission control unit
6 3 Cylinder #6 misfire
6 4 Cylinder #5 misfire
6 5 Cylinder #4 misfire
6 6 Cylinder #3 misfire
6 7 Cylinder #2 misfire
6 8 Cylinder #1 misfire
7 1 Multiple cylinder misfire
7 2 Three way catalytic converter (right side)
7 3 Three way catalytic converter (left side)
7 4 Evaporative emission control system pressure sensor
7 5 Evaporative emission control system
7 7 Rear O2 sensor
8 1 Vacuum cut valve bypass valve
8 2 Crank position sensor
8 3 Absolute pressure sensor
8 4 Automatic transmission control unit
8 6 Evaporative emission canister purge control solenoid valve
8 7 Evaporative emission Canister purge control solenoid valve circuit
9 1 Front Right O2 sensor
9 3 Evaporative emission Canister vent control valve
9 5 Crankshaft position sensor
9 8 Engine coolant temperature sensor
10 1 Front left O2 sensor
10 3 Park and Neutral position switch
10 5 EGRC solenoid valve
10 8 Evaporative emission canister purge volume control valve
11 1 Inhibitor switch
11 2 Revolution sensor
11 3 Improper shifting to first gear (Automatic transmission)
11 4 Improper shifting to second gear (Automatic transmission)
11 5 Improper shifting to third gear (Automatic transmission)
11 6 Improper shifting to fourth gear (Automatic transmission)
11 7 Solenoid valve lock up function
12 1 Shift solenoid B (Automatic transmission)
12 3 Overrun clutch solenoid valve (Automatic transmission)
12 4 Torque converter clutch solenoid valve (Automatic transmission)
12 5 Line pressure solenoid valve (Automatic transmission)
12 6 Throttle position sensor (Automatic transmission)
12 7 Engine speed signal
12 8 Fluid temperature sensor
13 2 MAP/BARO Switch Solenoid Valve
13 5 Fuel pump control module
13 8 Cooling fan