P1606

Originally Posted by SteveSAS

I've seem relays cause issues when they are loose in the car and bouncing around. The shock on the relay will cause the contacts to open for a few milliseconds but is enough to trip a error code. Other cases with age the electromagnet isn't strong enough and any little bump with cause it to open. Easy to find by tapping with a large screw driver with car running. Sometimes corroded connector or faulty crimp. could be many other reasons.
No easy way to fix, you just need to keep looking and rule things out.
At least you now know the area where the issue maybe.

Originally Posted by bunk

How hard do you have to tap on the relay when the engine is running? I tried that yesterday, but maybe I wasnt tapping hard enough. I also tried to push down on the relay.

Originally Posted by SouthArk370Z

Depends on where you hit it (parallel or perpendicular to the movable contacts) and how marginal the relay is. You can give them a pretty good whack without doing any damage; they get bounced around quite a bit in normal use.