Q: car cranks but wont start. check engine light on. code p0685

asked by on

Drove home from work, stopped on my way. car would crank but not start. my dash said "engine power reduced" i unhooked the battery and came back to the car an hour or so later and it started right up, I drove it about 3 miles and same thing, except this time it happened while i was driving. I called a tow truck driver and when he got there he jump started the car and it started right up on the first try. "Engine power reduced" warning went away but check engine light came on. I bought a code reader and it gave me p0685 "Ecn/pcm power control module relay/open". Car starts anytime i try to start it now, but i dont want to drive it anywhere and have to get it towed home again.

My car has 149000 miles.
My car has an automatic transmission.

The code P0685 indicates a problem with Engine Control Ignition Relay Control Circuit. This may have a poor connection or need to be replaced. I would recommend having an expert from YourMechanic come to your home to diagnose and repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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!
  1. Home
  2. Questions
  3. car cranks but wont start. check engine light on. code p0685

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: Engine clicks but won't start.

Hi, thanks for writing in. Your car is well known for having faulty starter motors. Since the battery is fine, it is very likely the your concern is due to a bad starter. Unfortunately, part of the intake manifold needs...

Q: Traction control off & it make a little jump

The traction control (TC) service light signifies that diagnostic trouble codes have been set. Those trouble codes should be downloaded and evaluated in a TC diagnostic. Although the TC trouble codes would be immediately downloaded in a diagnostic, the mechanic's...

Q: Truck not starting properly.

Hello, there are two different directions for a no start. The first being the starter doesn't work to start the engine. There are two thing to check here: that the base motor turns over manually, and that there is power...

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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
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.