Skip the auto shop - Our mechanics make house calls

Q: When trying to start it only clicks on a large relay (?ECU?) under the dash passenger side.

asked by on

Completely crapped out all at one time. parked it and the next day it would not show indicators or beep or nothing. slowly it started to show indicators even while the car was stopped and key removed. Then this clicking sound started under the dash on the passenger side. When I run the part number it says ECU. Does this need replacement?

My car has 85000 miles.
My car has an automatic transmission.

A: Often times when there is a starting issue,...

Often times when there is a starting issue, there is a small part called a starter relay that is many times over looked that is usually a fairly simple and inexpensive fix. The starter relay is a small unit near the starter that directs power to the starter from the battery. When this fails, it may cause a clicking sound and will not allow the starter to engage the flywheel when you turn the key. I would suggest starting with this first before going into a much more expensive repair like an ECU. If you would like to have this taken care of, a qualified professional from YourMechanic can diagnose the starting problem and guide with proper repairs.

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・Save up to 30%

Get a quote

What others are asking

Q: I got a message stating "Starting disabled theft problem" and the car will not start.

Hi there, thanks for writing in about your 2011 BMW 335 xDrive. It could be a low voltage situation with the battery. It can also be the key itself or the ignition switch. If you have access to a volt...

Q: Windshield wipers only go one speed

The wiper high low relay, or fuse may be bad. I recommend having a mechanic, such as one from YourMechanic, inspect your windshield wipers, in order to identify and quote the repairs needed.

Q: I had an oil change and Castrol GTX was used, which I assume is not a synthetic oil. Will that harm my engine.

Synthetic vs conventional oil is one of the most debated myths surrounding the topic of oil changes. This will not hurt your engine when switching from synthetic to conventional or vice versa. In fact, Synthetic blend oils are actually a...

Related articles

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...