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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: RPM revs high

Hi and thanks for contacting YourMechanic. Check the IAC (idle air control valve) to the engine. This will cause the RPM's to fluctuate up and down to a dramatic amount. Look at the wiring to the IAC and make sure...

Q: blown engine

When you want to do an engine swap with the exact same engine then you do not have as many challenges. When you want to change out a 4 cylinder to a 6 cylinder of an earlier year, you will...

Q: Car cannot be started

Hello. It sounds like your car’s battery is starting to go bad or is bad already. It doesn’t sound like a serious problem with the engine exists. In addition to the possibility that you have a bad battery, it is...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
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.