4T40E , 4T45E DTCs P0753 , P0758 , P1860 and Possible Engine DTCs - L61 LD9 LN2 - intermittent MIL no shift shudder slip transmission

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

The 4T40E and 4T45E automatic transmission may experience DTCs of P0753, P0758, P1860 and possible engine DTCs related to the Evap Canister Purge solenoid, A/C Compressor Switch relay and the heater element of the O2 sensor.

Splice S107 should be inspected for corrosion and or a poor connection. Splice S107 is the power source for pin E of the transmission pass through connector and provides voltage to the A and B shift solenoids and to the PWM TCC solenoid. In addition S107 supplies voltage to the Evap Canister Purge solenoid, A/C Compressor Switch relay and the heater element of the O2 sensor.

The engine wire harness conduit should be positioned or a hole should be cut in the conduit to prevent water from collecting in the conduit.

S107 is located near the front left side of the engine approximately 13 inches (0.33 m) from the Fuse Block-Underhood breakout on the LN2 and LD9 engines and for the L61 engine S107 is located in the engine harness at front left side of the engine approximately 5.31 inches (0.13 m) from the cooling fan connector breakout. SI document ID number 788529 provides a wiring schematic that shows the circuits related to S107.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.