Skip the auto shop - Our mechanics make house calls

Q: Wonky cruise control and rough idle on low gear D

asked by on

Just a little background, my car is giving me two codes. P0770 for shift solenoid e and a Low Emissions Efficiency. I drive my car regularly and take it on thousand mile trips every other week. The problem I'm having is that the cruise control is unreliable. Sometimes it will be on for hundreds of miles and other times it will flicker and turn off the whole ride. My mileage seems pretty good and the ride is very smooth. However, at red lights and stops the car vibrates a lot. It can be overwhelming at times. Regardless, the car itself runs really well and it has never stalled on me.

My car has 150000 miles.
My car has an automatic transmission.

A: Hello. P0770 is the code for a lock up torq...

Hello. P0770 is the code for a lock up torque converter shift solenoid malfunction. The lock up torque converter shift solenoid controls the fluid pressure of the torque converter, and the rate and timing at which it locks up. This may be the reason behind your intermittent issue. However, similar symptoms can be caused by many things. The cruise control is tied into the engine management system so it may also be possible that a sensor or wire is also causing the issue. Low speed engine vibrations can be caused by many things. I would first try to determine if the vibration is engine, transmission, or chassis-related. A few causes for vibration are engine misfires, worn motor or transmission mounts, or worn suspension components or tires. If you would like have to have this checked, a certified professional from YourMechanic can come to your car's location to diagnose the rough idle and cruise control problems.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: AC not blowing cold air

Hi there. From the description you have given, your vehicle's inoperative a/c could be a warrantable situation. If, the car lot won't take care of your vehicle's a/c, then confirming the diagnoses is very important. It could be, the a/c...

Q: Power steering - 2007 Pontiac Grand Prix

Hi. It is very difficult to tell you size of the belts that would needed to eliminate the power steering pump without measuring some things on the car. If I had to guess, you may need a belt that is...

Q: No heat?

You most likely have low coolant in the system and need to purge the air out of the cooling system. Have the cooling system checked and purged of air then test the heater again.

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.