I read through both codes. I feel the 1719 is being caused by the 742. The P0742 indicates the torque converter clutch (TCC) is stuck open. When that happens, the shifting you feel is what is expected.
Now, to confirm this is the problem, you need to follow a diagnostic flow chart which will require an upper level scan tool. I don't know if you have something that would work for this, but here is the flow chart which includes the code's description:
2007 Suzuki Truck XL-7 4WD V6-3.6L
Vehicle ALL Diagnostic Trouble Codes ( DTC ) Testing and Inspection P Code Charts P0742
Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure.
Review [Strategy Based Diagnosis] for an overview of the diagnostic approach. See: Vehicle > Initial Inspection and Diagnostic Overview > Strategy Based Diagnosis
[Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category. See: Vehicle > Initial Inspection and Diagnostic Overview > Diagnostic Procedure Instructions - Vehicle Diagnostic Information
DTC P0742 Torque Converter Clutch (TCC) System - Stuck On
The transmission control module (TCM) controls the torque converter clutch (TCC) lock up pressure control solenoid valve. The solenoid directs the hydraulic fluid for TCC apply and release. When the TCC is released, the engine is coupled by fluid to the transmission.
Conditions for Running the DTC
No Throttle Position (TP) Sensor DTC P0120
No Transmission Range (TR) Switch DTC's P0706, P0707, or P0708
No Transmission Fluid Temperature (TFT) Sensor DTCs P0711, P0712, or P0713
No Speed Sensor DTC's P0717, P0722, P0727
No Pressure Control (PC) Solenoid DTCs P0962, P0963, P0966, P0967, P0970, or P0971
No Shift Solenoid (SS) Control Circuit DTC's P0973, P0974, P0976, P0977, P0979, P0980, P0982, P0983, P0985, or P0986
No Transmission Torque Delivered Circuit DTC P2637
No Communications DTC's U0100 or U2104
Engine speed is greater than 400 RPM
Input Speed is less than 3000 RPM
Range equals D, M, or L for 8 seconds
Transmission oil temperature is greater than 20 C
Engine torque is 46 - 240 Ohms
The ignition voltage is greater than 10.5 volts
Conditions for Setting the DTC
Engine speed minus input speed is less than 50 RPM for 12 seconds when the TCC is commanded off. Low torque converter slip.
Action Taken When the DTC Sets
The transmission will operate in 5th gear in D range, 2nd gear in L range.
Conditions for Clearing the DTC
DTC P0742 is a Type A DTC
Improper transmission fluid level may cause DTC P0742 to set.
1. Ignition ON, observe the DTC information with a scan tool.
2. Record Freeze Frame and Failure Records.
3. Clear DTC's.
4. Operate the vehicle under the conditions observed in the Failure Records.
5. Observe the DTC information with the scan tool. Verify that the DTC does not set.
6. Operate the vehicle in D (drive). Using a scan tool, observe the TCC Slip Speed parameter in 3rd, 4th, and 5th gear while the TCC PC Sol. Ref. Current parameter is less than 100 mA. The TCC Slip Speed parameter should be greater than 50 RPM.
1. Engine ON, apply the parking brake, select P (park) using the Shift Control.
2. Observe the scan tool Transmission ISS parameter. The reading should be within 400-800 RPM.
> If the ISS parameter is not within the specified range, test or replace the Transmission Input Speed Sensor (ISS).
3. Perform a line pressure test.
4. Remove the Control valve body cover.
5. Inspect the inside of the control valve body cover for excessive sediment. There should not be excessive sediment.
> If excessive sediment is found inspect and replace as necessary the Torque converter assembly, Input shaft, and Fluid pump stator shaft assembly. If all conditions test normal, test or replace the transmission.
6. Verify that the control valve body has been serviced within the past 3 months.
> If the control valve body has not been serviced, replace the control valve body assembly. If all circuits and components test normal, replace the transmission.
7. If all circuits and components test normal, replace the transmission.
Perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure.
Note that there are many other things, as listed above, that can be causing the code.
Let me know if this helps or if you have other questions.
Monday, July 20th, 2020 AT 1:59 PM