i have a question i have a 2010 buick lacrosse cxl
and i have a problem with the transmission
when i start the car in the morning when the car is cold
when start running the car ..the car will goes from third speed to second speed
and it will not shift
i need to turn the car off and turn it on back two times and it start working properly after that
i have scan it and it show p0989 transmission fluid pressure sensor
what will be the problem how can i fix it
The Diagnostic Trouble Code P0989 can set due to the following causes: Defective transmission fluid pressure sensor; Malfunctioning electronic pressure control solenoid; Defective electrical components, such as wires, connectors, and fuses; Insufficient transmission fluid levels; Dirty transmission fluid; Blockages within the hydraulic pressure system; Problems within the internal transmission; and in rare (very exceptional) cases, a faulty PCM, or transmission control module.
You should check the transmission fluid level first. If it is below the minimum level, that could account for your issue although, even if the fluid level is OK but it is contaminated, that could account for the problem.
If there is no issue with the fluid level or quality, a mechanic, like one from YourMechanic, will have to methodically go through each of the other listed possible causes during a Pressure Switch diagnostic. Best of luck.