Bad main relay symptoms

Philcarnews.com prepared some of the signs of a bad main relay, and they are the following:

• The engine does not start.
• The car is incapable of running for a long time interval.
• The car starts sometimes, and sometimes it doesn't.
• Check engine light alights.
• The car won't start once the interior's gotten hot.

1. How do I know if my main relay is bad?
2. What can a bad main relay cause?
3. What does the main relay control?
4. Can a car run without main relay?
5. Can a main relay drain battery?
6. What does a bad relay sound like?
7. How long do main relays last?
8. Can I drive with a bad relay?
9. How do you know if a relay fuse is blown?
10. How do you test a relay?
11. Will a bad relay still click?
12. How do you know if you need a new relay?
13. Will a bad relay throw a code?
14. Can I drive with a bad relay?

How do I know if my main relay is bad?

Common signs include the engine not starting, inability to stay running for a long time, and the Check Engine Light coming on.

What can a bad main relay cause?

If the relay fails it will cut off power to fuel pump and ignition system, which will result in a no power, and therefore no start condition. You may find that turning the key may power on the accessories, and may even crank the engine.

What does the main relay control?

The main relay in a vehicle controls the fuel pump and supplies power to the injectors. Knowing how to test a Honda main relay can help you better pinpoint the cause when an electrical issue arises.

Can a car run without main relay?

Without an operational main relay, your car will not operate. However, electrical problems can be complex, and the failure of the main relay could possibly be a symptom of an underlying problem.

Can a main relay drain battery?

A failed ECM power relay can also cause a battery drain or dead battery. If the relay shorts it can leave power on to the computer, even when the vehicle is turned off. This will place a parasitic drain on the battery, which will eventually cause it to go dead.

What does a bad relay sound like?

A faulty relay often produces an audible clicking sound when you turn your car. Contact a mechanic immediately if your car fails to start and you notice this sound.

How long do main relays 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.

Can I drive with a bad relay?

If the relay has any sort of issue it may compromise power to the computer, which will not allow the vehicle to start. For many vehicles the engine's starting circuit is on a separate circuit and relay than the computer's, so the engine will still crank even if the computer relay has failed.

How do you know if a relay fuse is blown?

The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).

How do you test a relay?

Take the leads of the multimeter and connect them across the coil terminals of the relay. For a normal coil, the multimeter should read anywhere between 40Ω to 120Ω. If the coil is damaged i.e., it is open, the meter shows out of range and you have to replace the relay.

Will a bad relay still click?

A faulty relay often produces an audible clicking sound when you turn your car. Contact a mechanic immediately if your car fails to start and you notice this sound.

How do you know if you need a new relay?

You want to feel and listen for any clicks. If you feel and hear clicks, the relay works on one side – the side with the energizing circuit and coil. However, if there was no sound from the horn, the relay has a problem along the contact circuit.

Will a bad relay throw a code?

As was mentioned, a bad fuel pump relay can cause a code to be set in the PCM, but only on certain cars.

Can I drive with a bad relay?

If the relay has any sort of issue it may compromise power to the computer, which will not allow the vehicle to start. For many vehicles the engine's starting circuit is on a separate circuit and relay than the computer's, so the engine will still crank even if the computer relay has failed.