When you start your car, a number of things happen. The fuel pump delivers gas through the fuel lines to the fuel injectors, and the battery delivers voltage to the ignition which sparks, ignites the fuel vapor, and causes the engine to turn over. All of this depends on the automatic shutdown relay – it works every time you start your engine, just for a few seconds, and then it turns itself off. If the automatic shutdown relay doesn’t work, then nothing works.

The life of your automatic shutdown relay depends on a lot of different factors. Obviously, how often you drive will affect the life of the relay. Also, the more often you start and stop and then start again, the more often the relay has to work, and since the life of a relay is measured in cycles, as opposed to miles driven or years, this can also reduce the time you can expect it to last.

Most relays are rated for about 50,000 cycles, so it is possible that the automatic shutdown relay will last you the life of your car. However, if it does fail, you won’t be going anywhere until you have it replaced. Signs that your automatic shutdown relay needs to be replaced are:

  • Engine will not crank when you turn the key in the ignition
  • Engine cannot be jump started
  • Check Engine Light is on
  • Engine starts but then stalls out

If your car won’t start, a professional mechanic can diagnose your starting problems, and if necessary, replace the automatic shutdown relay.

This article originally appeared on YourMechanic.com as How Long Does an Automatic Shutdown Relay Last? and was authored by Valerie Johnston.


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