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: Dome light unit fell down

The sun visor has no serviceable parts and would need to be replaced if it is unable to stay in its stowed position. If the mounting hardware on the dome light is damaged then the dome light assembly will need...

Q: Brake Pedal feels loose have to push all the way down pumping it helps stop it but mostly it keeps sliding until I pull E-brake.

Hello. After replacing any brake hose or line, the brake system has to be bled of any air. Did your friend do that after installing the hose? Try bleeding the entire brake system. If the seal under the brake fluid...

Q: SUV stops & idles at red lights

I would recommend having your alternator tested. If the voltage regulator inside the alternator has failed allowing the alternator to overcharge the battery, symptoms such as the one your described may occur. These symptoms would be the result of the...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...