Q: Car won't start, is it my ECU?

asked by on October 10, 2016

So, my car battery died because I left the keys in the ignition for 2 weeks, not in the on position, just in the ignition. So we jumped it & all was well. Unfortunately I didn't drive it or let it run long enough, so in the morning it was dead again. So my boyfriend jumped it again, this time he crossed the cables & it caused a spark of course. He then put them on the correct way & the car started. We drove around fine but the radio wasn't working. I found that it blew the radio fuse. The radio came on but I have no sound with the radio, only sound on the right side when a cd is in. Well now the car tries to start but it won't fully turn over. Could it be the ECU? We got the P1122 code for the throttle control actuator & are going to look into the fuel pump & I will be getting a new battery but I just need to know what else it could be? Please help, I just got the car 2 months ago & have only driven it twice.

My car has 120000 miles.
My car has an automatic transmission.

Car is not starting Inspection $94.99 - $114.99 Get a Quote

Hi, thanks for writing in. While it could be the ECU, it could also be a great many other things. It is most likely not any one component but is probably a combination of faults. Many years ago you could get away with crossing the cables with little more damage than an alternator, but the electronics in modern cars are very sophisticated and are easily damaged by voltage spikes. You probably have a surge protector on your computer at home to protect it from just the sort of thing that happens to the electronics in your car if you get your cables crossed. There is no easy answer for this problem and simply replacing every component that shows up in the list of codes can get very expensive and very likely won’t solve all of your problems. This is one case where you really need someone with experience to sort it out. Here at YourMechanic, we can have a technician come to your home or office to inspect and diagnose this issue for you, and make or suggest the necessary repairs.

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do you operate the hazard lights?
If you are ever stranded on the side of the road, you’ll need to use your hazard lights to warn other drivers of your presence. Depending on where you live, it may also be legal to use your hazard lights...
Electrical problems with car
Hi there. On the right front wheel well, there are a series of fusible links which distribute battery power to all of the vehicle's electrical systems. One is gray and is labeled "fusible link K," which supplies power to all...
Injector clogged metal shavings
Hello there, having faults within the first 5000 miles is not uncommon. This is the time where any faults from the factory will show themselves. It is entirely possible that through the manufacturing process, a piece of metal worn off...
New Slave cylinder installed and the plunger keeps getting dislocated. Doesn't want to go back into the cylinder and the pedal is soft
Hey there, it sounds as though the hydraulic pressure is not bleeding back fully when you release the pedal. First you should check the clutch pedal and verify that there is free play when the pedal is released. There should...
i have a 2005 dodge ram 1500 that makes a clicking noise when i turn what is this
If your vehicle is 4WD with CV axles in the front, a common cause of clicking and clunking in the circumstances that you describe is a faulty outer CV joint. Such can often be detected on visual exam and with...
The turn signal blinks rapidly so I replaced and it worked ok but then blinked rapidly again after awhile then rapidly again.
What you are describing sounds like a bad turn signal flasher (https://www.yourmechanic.com/services/hazard-turn-signal-flasher-replacement). The flasher unit is an electrical unit that is usually located under the hood and is wired with the turn signal lights. This flasher sends short intermittent bursts...
How to clean my Turbo
Hi Davon. Thanks for contacting us today. Many people think that using Sea-Foam or other carbon cleaning agents is the best way to clean a turbo-charged, fuel injected system. However, Hyundai recommends a rather specific procedure be completed for their...
battery light came on while driving; alternator or battery issue
The battery/charging warning light could pertain to the battery, the charging system, wiring faults, or even a loose drive belt that is not properly driving the alternator. The exact circumstances would have to be determined by looking at the car....
Ignition problem
Most vehicles have an ignition switch actuator, or comparable device, and if that component fails, the symptom you describe is exactly what occurs. The diagnosis of this, and the likely part replacement, can be performed at your location. If you...

Related articles

2007 Nissan Versa vs. 2007 Saturn Ion: Which One Should I Buy?
Compact cars as a class are generally meant to be commuter vehicles: with excellent gas mileage, an entry-level price point, and decent safety ratings for those who are on the road the majority of their time. These cars also make...
The Best Used Cars to Buy If You Like to Go Off-Roading
Your Your best bet for off-roading is a 4x4 SUV. Depending on the model that pleases you most, though, you might have to shop around a bit to find a good used one. That’s simply because off-roaders typically become very...
The Best Used Cars to Buy If You're a Teacher
If If you are a teacher, probably foremost on your mind is getting to school on time. You would also probably like a used car that is easy on gas and not terribly expensive, and will hold your gym gear...