STORED CODES P0128, P1811. delayed lockup

Question

TRANS NOT SHIFTING PROPERLY (DELAY) TO LOCKUP ON THE HIGHWAY. P1811 AND P0128 ARE HARD CODES BUT TWO PREVIOUSLY STORED CODES THAT DID NOT RETURN ARE C1298 AND P1626. ARE ANY OF THESE DTC'S RELATED OR COMMON TO OCCUR TOGETHER? WHAT ARE THE CONDITIONS TO SET THE P1811 CODE? CAN A PROBLEM WITH THE THERMOSTAT CAUSE THE TRANS MODULE TO SET THE P1811? THANKS!

Answer 1

P1626 Theft deterent signal

P0128 Coolant thermostat malfunction

P1811 Adaptive shift time

P1811 can be caused by the transmission filter missing O-ring,or in the valve body misaligned spacer plate or valve body gasket, or even a faulty transmission oil pump, Over all this can not be caused by a faulty thermostat, Your transmission has low pressure, It is very common for the fault  to be with the transmission pump.You can try transmission additive for this.