Q: accidentally hooked up jumper cables backwards. No there is no spark on plugs and the fuel pump is running with the engine off.

asked by on

hi my battery was going dead old battery so i went to jump it and by mistake with my small jumper i hooked it up wrong and real quick put it and off and i herd the spark after this the car did't start. i replaced the battery and starter and one relay in the front compartment becouse it was buzzing. Now the car cranks but it not giving me any spark.The code reader showing me DTC module U114B U115E U115B U114E.and Fuel pump. About the fuel pump, I can hear it running on and off when the car is off.What controls the pump to go on and off.

My car has 107356 miles.
My car has an automatic transmission.

Hi there. The U codes are for the body portion of the electrical system. U114 codes are designated to the fuel system. If the fuel pump is working but all of a sudden it is coming on when the engine is off, then there is a major short in the electrical system of the vehicle. The U115 codes relate to the PCM (computer) not working properly. Since jumper cables were hooked up backwards, the shock of the power most likely burned up the PCM (computer) to the car. I recommend replacing the PCM (computer) and installing a new battery. If you need further assistance with your electrical system, then seek out a professional, such as one from Your Mechanic, to help you.

Was this answer helpful?

Hello - the engine management computer controls the fuel pump (through a relay). The lack of spark may be related to a failed crankshaft position sensor, or possibly one or more of the coil packs. Failure of these will yield a "no spark" condition. The codes you list are "BMW-proprietary", making them less useful. Further diagnosis is needed to work back up the "ignition" path to determine the failed component. I would recommend an engine ignition system inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. accidentally hooked up jumper cables backwards. No there is no spark on plugs and the fuel pump is running with the engine off.

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: What could be causing the serious vibrations in the steering column and front end when the truck exceeds 35 mph?

Hello, thank you for writing in. The most common issues with vibrations at higher speeds are related to the tires or suspension. The first place to start is having the tires inspected. Make sure the tread is deep enough, the...

Q: Hi I have a 2005 Hyundai Santa Fe 2.7 and it turns over but I can't get it to start.

Hi, thanks for writing in. You will first need to scan the computer and check for any codes stored in the computer. Your computer should have codes stored if there is problems with the camshaft sensor or mass air flow...

Q: Fuel gauge acting erratically

It's possible that you have a problem with your fuel gauge. The only way to tell is to pull the fuel pump out and check resistance on the sending unit. I would suggest having a certified technician come out and...

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 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...
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.