Shift light flashing changed transmission \coil ecm\pcm transmission module diagnostics cyl missfire invalid data u0401

The P0700 code indicates that there's a malfunction with your vehicle's Transmission Control Module (TCM). This computer monitors your transmission and works with the Powertrain Control Module (PCM) and Engine Control Module (ECM) to shift gears when necessary
copy and paste
https://www.solopcms.com/blog/p0700-code-means-fix/

Hooking up a factory or someother type professional scan tool an checking for DTC'S - diagnostic trouble codes stored in the 4X4 control module is the proper way to start diagnostics . Your best bet ,have a qualified repair shop check it out .

Principles of Operation
The electronic shift on the fly (ESOF) system is an electronic shift system that allows the operator to choose between 2 different 4-wheel drive modes as well as 2-wheel drive. The operator can switch between 2WD and 4H mode at speeds up to 88 km/h (55 mph). To engage or disengage 4L range, the vehicle speed must be less than 5 km/h (3 mph), the brake pedal pressed and the transmission must be in NEUTRAL (or the clutch pedal pressed in manual transmission vehicles).
When the mode select switch (MSS) on the instrument panel is turned, the 4WD control module (PCM) activates the electromagnetic clutch and powers the transfer case shift motor. When the shift motor reaches the desired position, as determined by the contact plate position inputs to the 4WD control module (PCM), power to the shift motor will be removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the mainshaft hub to the drive sprocket. Finally, the front axle integrated wheel ends (IWEs) are engaged and the electromagnetic clutch is deactivated.

Feature Inputs:
• Mode select switch (MSS)
• Wheel speeds (via CAN communication)
• Contact plate position inputs A, B, C, D (grounded when closed, open circuit when open)
• Transmission neutral
• Brake ON/OFF (BOO)

Feature Outputs:
• Transfer case synchronization clutch
• Transfer case shift motor relays
• Integrated wheel-end (IWE) vacuum solenoid
• Instrument cluster indicators (via CAN communication)
• 4WD mode (via CAN communication to PCM)
• Inspection and Verification
  
  1. Verify the customer concern.
  1. Visually inspect for obvious signs of mechanical or electrical damage.
  
  
  Visual Inspection Chart Mechanical Electrical
  • Halfshafts
  • Integrated wheel ends (IWE)
  • Shift motor
  • Driveshaft and universal joints
  • Vacuum leaks
  • Fluid leaks
  • Matching tire sizes
  • Transfer case
  • Central junction box (CJB) mini fuses:
    • 11 (10A) (IWE vacuum solenoid)
    • 28 (5A)
    • 29 (15A)
    • 30 (15A)
  • CJB fuse 111 (20A)
  • Wiring harness
  • Mode select switch (MSS)
  • Synchronization clutch
  • Connector(s)
  • IWE vacuum solenoid
  • Circuitry
  
  
  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
  1. If the cause is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
  • check that the program card is correctly installed (if using NGS+).
  • check the connections to the vehicle.
  • check the ignition switch position.
  1. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
  1. Carry out the data link diagnostics test. If the diagnostic tool responds with:
  • SCP+, SCP-, UBP, CAN or ISO circuits fault; all electronic control units no response/not equipped, refer to Section 418-00 .
  • No response/not equipped for powertrain control module (PCM). Refer to Section 418-00 to diagnose module communication problems.
  • No response/not equipped for 4WD control module (PCM), Go To Pinpoint Test J .
  • System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the self-test diagnostics for the 4WD control module (PCM).
  1. If the DTCs retrieved are related to the concern, go to the 4WD Control Module (PCM) DTC Index to continue diagnostics.
  1. If no DTCs related to the concern are retrieved, GO to Symptom Chart .
  2. 4WD Control Module (PCM) Diagnostic Trouble Code (DTC) Index
     DTC Description Source Action B1317 Battery Voltage High 4WD Control Module (PCM) CHECK the battery and charging system for faults. REFER to Section 414-00 . CLEAR the DTC. REPEAT the self-test. B1318 Battery Voltage Low 4WD Control Module CHECK the battery and charging system for faults. REFER to Section 414-00 . CLEAR the DTC. REPEAT the self-test. B1342 ECU is Defective 4WD Control Module CLEAR the DTC. REPEAT the self-test. If DTC B1342 is retrieved, INSTALL a 4WD control module (integral to the PCM). REFER to Section 303-14 . REPEAT the self-test. C1728 Transfer Case Unable to Transition Between 2WD HIGH and 4WD HIGH 4WD Control Module Go To Pinpoint Test L . C1729 Transfer Case Unable to Transition Between 4WD HIGH and 4WD LOW 4WD Control Module Go To Pinpoint Test M . C1979 IWE Solenoid Circuit Failure 4WD Control Module Go To Pinpoint Test K . C1980 IWE Solenoid Circuit Short to Battery 4WD Control Module Go To Pinpoint Test K . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure 4WD Control Module Go To Pinpoint Test L . P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground 4WD Control Module Go To Pinpoint Test L . P1820 Transfer Case Clockwise Shift Relay Coil Circuit Failure 4WD Control Module Go To Pinpoint Test L . P1822 Transfer Case Clockwise Shift Relay Coil Short Circuit To Battery 4WD Control Module Go To Pinpoint Test L . P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure 4WD Control Module Go To Pinpoint Test N . P1826 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery 4WD Control Module Go To Pinpoint Test N . P1827 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Ground 4WD Control Module Go To Pinpoint Test N . P1828 Transfer Case Counterclockwise Shift Relay Coil Circuit Failure 4WD Control Module Go To Pinpoint Test L . P1830 Transfer Case Counterclockwise Shift Relay Coil Short Circuit To Battery 4WD Control Module Go To Pinpoint Test L . P1849 Transmission Transfer Case Contact Plate A Short Circuit to Ground 4WD Control Module Go To Pinpoint Test L . P1853 Transmission Transfer Case Contact Plate B Short Circuit to Ground 4WD Control Module Go To Pinpoint Test L . P1857 Transmission Transfer Case Contact Plate C Short Circuit to Ground 4WD Control Module Go To Pinpoint Test L . P1861 Transmission Transfer Case Contact Plate D Short Circuit to Ground 4WD Control Module Go To Pinpoint Test L . P1867 Transmission Transfer Case Contact Plate General Circuit Failure 4WD Control Module Go To Pinpoint Test L . P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit 4WD Control Module Go To Pinpoint Test L . U1900 CAN Communication BUS Fault - Received Error 4WD Control Module DIAGNOSE the module communication network. REFER to Section 418-00 . U2023 Fault Received From External Node 4WD Control Module DIAGNOSE the module communication network. REFER to Section 418-00 . U2051 One Or More Calibration Files Missing/Corrupt 4WD Control Module Method 3 programming fault. REFER to Section 418-00 for 4WD control module (PCM) programming information.

Circuit Description
Modules that are connected to the shared communication circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have pre-recorded information about what messages are needed to be exchanged on the serial data circuits for each virtual network. The messages are usually supervised and some periodic messages are used by the receiver module as an availability indication of the transmitter module.

DTC U0401 TCM received invalid data from ECM
Conditions for Setting the DTC
The transmission control module (TCM) detects an invalid throttle position signal, engine speed signal and/or engine coolant temperature signal for more than 2 seconds.

Action Taken When the DTC Sets
• The TCM will store the DTC when a failure is detected on the first ignition cycle.
• The TCM will illuminate the HOLD lamp.
• The TCM can no longer determine the validity of any information it may or may not receive from the engine control module (ECM). Therefore the TCM substitutes default values for engine speed, throttle position, and other engine data signals.
• Transmission operation will be reduced, affecting shift points, torque converter clutch operation, and other driveability concerns.

Diagnostic Aids
• An intermittent malfunction may be caused by a fault in the electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions in Engine Controls 1.6L.
• Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.
• Faulty ECM and/or TCM

Install a scan tool.
Turn ON the ignition, with the engine OFF.
Save the DTC and Freeze Frame information into the scan tool memory.
Perform the scan tool Clear DTC Information function for the transmission control module (TCM) and the engine control module (ECM).
Operate the vehicle for 1 minute or until the MIL illuminates.
Check the TCM for DTCs.
Is the Malfunction Indicator Lamp (MIL) On?
--
YES - Go to Step 2
NO - Repair the wiring connectors for intermittent failure

Select request DTC status from the Diagnostic Trouble Codes Information menu
Request DTC by status
Is DTC U0401 displayed?
--
YES - Go to Step 3
NO - Repair the wiring connectors for intermittent failure
3
Turn OFF the ignition.
Disconnect connector A from the TCM.
Turn the ignition ON, with the engine OFF.
Measure the resistance between terminal A17 of the TCM wiring connector and terminal K14 of the ECM wiring connector.
Measure the resistance between terminal A7 of the TCM wiring connector and terminal K15 of the ECM wiring connector.
Was the resistance the specified value for both circuits?
0 ohms
YES - Go to Step 5
NO - Go to Step 4

The overdrive light flashing indicates there is a problem an a DTC diagnostic trouble code is stored in the PCM - engine computer or the Transmission control module ! Your best bet is to take it to a ASE certified repair shop or the dealer . you don't have the diagnostic tools or knowledge to fix this 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 the PARK position. The system consists of the following components:
?€¢
The automatic transmission shift lock control solenoid

?€¢
The automatic transmission shift lock control switch
Can you or can you not take it out of park ?
Shift Lever Does Not Move with Brake Pedal Depressed
yes or no ?
PRND321 Display
The instrument panel cluster (IPC) displays the selected gear position as determined by the engine control module (ECM). The IPC 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.

You have a transmission range sensor or PCM problem , Need a professional grade scan tool to diagnose the problem , well that would be the easiest way to test .You should have all modules test for DTC'S - diagnostic trouble codes ! That would point you in the right direction ! I would suggest you google class 2 serial data communication network !

SWAP COIL LIKE FROM CYL NUMBER 1 TO 4 AND ROAD TEST UNDER LOADS IF CHANGE THE MISS TO CYL NUMBER 1 NEED A COIL OR BAD PLUG AT CYL NUMBER 4

The 4X4 system on your vehicle is computer controlled , GEM module . generic electronic module . The four wheel drive mode switch is a low voltage input to the GEM module . The GEM energizes relay's to control the mode as depicted by input from the mode switch an torque on demand relay an someother inputs . Probably has DTC - diagnostic trouble codes stored in the GEM module .
Transfer Case -Automatic Four-Wheel Drive (A4WD) The automatic 4-wheel drive transfer case system consists of the following:

• automatic 4WD indicator light
• brake pedal position (BPP) switch
• torque on demand (TOD) relay
• front output shaft speed sensor
• generic electronic module (GEM)
• 4WD high indicator light
• 4WD low indicator light
• 4WD mode switch
• rear output shaft speed sensor
• shift position sensor
• throttle position output (TPO) from the powertrain control module (PCM)
• transmission range sensor P1804 Transmission 4-Wheel Drive High Indicator Circuit Failure GEM REFER to Section 413-01 . P1806 Transmission 4-Wheel Drive High Indicator Short Circuit to Battery GEM REFER to Section 413-01 . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure GEM REFER to the Symptom Chart. P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground GEM GO to Pinpoint Test C . P1820 Transmission Transfer Case Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test B . P1822 Transmission Transfer Case Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test B . P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure GEM GO to Pinpoint Test A . P1826 Transmission 4-Wheel Drive Low Clutch Relay Circuit to Battery GEM GO to Pinpoint Test A . P1828 Transmission Transfer Case Counter Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test B . P1830 Transmission Transfer Case Counter Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test B . P1836 Transmission Transfer Case Front Shaft Speed Sensor Circuit Failure GEM GO to Pinpoint Test A . P1837 Transmission Transfer Case Rear Shaft Speed Sensor Circuit Failure GEM GO to Pinpoint Test A . P1838 Transmission Transfer Case Shift Motor Circuit Failure GEM REFER to the Symptom Chart. P1846 Transmission Transfer Case Contact Plate 'A' Circuit Failure GEM REFER to the Symptom Chart. P1850 Transmission Transfer Case Contact Plate 'B' Circuit Failure GEM REFER to the Symptom Chart. P1854 Transmission Transfer Case Contact Plate 'C' Circuit Failure GEM REFER to the Symptom Chart. P1858 Transmission Transfer Case Contact Plate 'D' Circuit Failure GEM REFER to the Symptom Chart. P1866 Transmission Transfer Case System Concern - Servicing Required GEM REFER to the Symptom Chart. P1867 Transmission Transfer Case Contact Plate General Circuit Failure GEM REFER to the Symptom Chart. P1874 Transmission Automatic Hall Effect Sensor Power Circuit Failure GEM GO to Pinpoint Test A . P1875 Transmission Automatic Hall Effect Sensor Power Circuit Short to Battery GEM REFER to the Symptom Chart. P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit GEM REFER to the Symptom Chart. P1892 Trans. Automatic 4-Wheel Drive 4X4 Mechanical Lock Output Circuit Failure GEM GO to Pinpoint Test B . P1893 Trans. Auto. 4-Wheel Drive 4X4 Mechanical Lock Output Short to Battery GEM GO to Pinpoint Test B .
• Your best bet , take it to a qualified repair shop .

There must have been a 'Check Engine' Light? When a 'check engine light' (MIL=Malfunction Indicator Lamp) is turned on, there is a DTC (Diagnostic Trouble Code) set/stored in the ECM/PCM (Engine Control Module/Powertrain Control Module). This code identifies which engine management system component/function experienced a malfunction. Once you pull/read this code, you may begin diagnosis. You'll need an OBDII (On-Board Diagnostics II) code reader. You should find a P07?? number stored (P07??... is a transmission code).

P0606
Control Module Internal Performance

P0601
Control Module Read Only Memory (ROM)
ECM, PCM
U0107
Throttle Actuator Control (TAC) Module Serial Data Circuit
ECM, PCM

The throttle actuator control (TAC) module and the powertrain control module (PCM) communicate using a dedicated serial data circuit. This serial data circuit is separate from any other serial data circuit on the vehicle. Accurate transmitting and receiving of serial data requires not only good circuit integrity but also adequate system voltage. This diagnostic monitors the accuracy of the serial data transmitted between the TAC module and the PCM. If the PCM detects a loss of data or invalid data, or if the throttle limit is exceeded while operating in the Reduced Engine Power mode, DTC U0107 sets.

Your best bet is going to be to take your vehicle to a GM dealer ! Cadillac , Buick

2-Speed Torque-On-Demand (TOD) Operation
The automatic 4-wheel drive (A4WD) system is a 2-speed torque-on-demand (TOD) operation that utilizes the following components:

• Transfer case
• 4-wheel drive (4WD) control module (integral to the powertrain control module [PCM])
• Mode select switch (MSS)
• Gearmotor encoder assembly (part of the transfer case shift motor)
• Transfer case shift motor
• Shift motor sense plate (part of the gearmotor encoder assembly)

Principles of Operation
Transfer Case Shift Motor The externally mounted transfer case shift motor, located at the rear of the transfer case, turns the shift cam assembly. As the shift cam assembly turns, it positions the reduction shift fork for desired transfer case operation. An integral position sensor in the shift motor provides shift motor position information to the 4WD control module.
Mode Select Switch (MSS) The push button MSS, mounted on the instrument panel, allows the operator to select the 4x4 Auto, 4x4 High, and 4x4 Low transfer case operating modes. The indicator light, on the instrument cluster push button, will illuminate only when the 4x4 Low position is engaged.
Visual Inspection Chart Mechanical Electrical

• Axle shafts and CV joints
• Driveshaft and universal joints
• Fluid leaks
• Matching tire sizes
• Transfer case shift motor

• Battery junction box (BJB) fuses:
  • 8 (30A)
  • 17 (5A)
  • 18 (20A)
• Central junction box (CJB) fuses:
  • 12 (5A)
  • 24 (15A)
• 4x4 module (PCM)
• Wiring harness
• Gearmotor encoder contact plate
• Connector(s)
• Circuitry
• Mode indication switch (MSS)

1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

1. If the concern is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
   • check that the program card is correctly installed.
   • check the connections to the vehicle.
   • check the ignition switch position.

1. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.

1. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
   • CAN circuit fault; all electronic control units no response/not equipped, refer to Section 418-00 .
   • No response/not equipped for 4WD module (PCM), Go To Pinpoint Test G .
   • System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the 4WD module (PCM) self test.

1. If the DTCs retrieved are related to the concern, go to the 4WD Control Module (PCM) Diagnostic Trouble Code (DTC) Index to continue diagnostics. 4WD Control Module (PCM) Diagnostic Trouble Code (DTC) Index
   DTC Description Source Action B1317 Battery Voltage HIGH 4WD Module (PCM) REFER to Section 414-00 . B1318 Battery Voltage LOW 4WD Module (PCM) REFER to Section 414-00 . B1319 Driver Door Ajar Circuit Failure 4WD Module (PCM) Go To Pinpoint Test M . B1322 Driver Door Ajar Circuit Short To Ground 4WD Module (PCM) Go To Pinpoint Test M . B1342 ECU is Defective 4WD Module (PCM) CLEAR the DTCs. REPEAT the 4x4 module (PCM) self test. If DTC B1342 is retrieved, INSTALL a new 4x4 module (PCM). REFER to Section 303-14 . CLEAR the DTCs. REPEAT the self test. B1483 Brake Pedal Input Circuit Failure 4WD Module (PCM) Go To Pinpoint Test M . B1485 Brake Pedal Input Short to Battery 4WD Module (PCM) Go To Pinpoint Test M . C1729 Transfer Case Unable to Transition Between 4H and 4L 4WD Module (PCM) Go To Pinpoint Test K . C1970 4WD Low Mode Switch LED Short to Battery 4WD Module (PCM) Go To Pinpoint Test K . C1971 4WD Low Mode Switch LED Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1707 Transfer Case NEUTRAL or PARK/NEUTRAL Indication Circuit 4WD Module (PCM) Go To Pinpoint Test M . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1816 Transmission NEUTRAL Safety Switch Circuit Failure 4WD Module (PCM) Go To Pinpoint Test M . P1819 Transmission NEUTRAL Safety Switch Circuit Short to Ground 4WD Module (PCM) Go To Pinpoint Test M . P1820 Transfer Case Clockwise Shift Relay Coil Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1822 Transfer Case Clockwise Shift Relay Coil Circuit Short To Battery 4WD Module (PCM) Go To Pinpoint Test K . P1824 4-Wheel Drive Clutch Relay Circuit Failure 4WD Module (PCM) Go To Pinpoint Test H . P1826 4-Wheel Drive Low Clutch Relay Short Circuit to Battery 4WD Module (PCM) Go To Pinpoint Test H . P1827 4-Wheel Drive Low Clutch Relay Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test H . P1828 Transfer Case Counterclockwise Shift Relay Coil Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1830 Transfer Case Counterclockwise Shift Relay Coil Circuit Short To Battery 4WD Module (PCM) Go To Pinpoint Test K . P1849 Transfer Case Contact Plate A Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1853 Transfer Case Contact Plate B Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1857 Transfer Case Contact Plate C Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1861 Transfer Case Contact Plate D Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1867 Transfer Case Contact Plate General Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1891 Transfer Case Contact Plate Ground Return Open Circuit 4WD Module (PCM) Go To Pinpoint Test K . U1900 CAN Communication BUS Fault 4WD Module (PCM) REFER to Section 418-00 . U2023 External Node Fault 4WD Module (PCM) REFER to Section 418-00 . U2051 One Or More Calibration Files Missing/Corrupt 4WD Module (PCM) Reprogram/Reflash the 4x4 module. REFER to Section 418-00 . - For All Other DTCs 4WD Module (PCM) REFER to Section 418-00 .
2. Your best bet mite be to take it to a qualified repair shop !