RD Stephenson

I have 01 Maxima and am having trouble with the fuel pump relay and was wondering if anyone has experienced this issue. I changed out the fuel pump relay but it will not click when the key is turned on. however, I can jump the relay and the fuel pump works and the car starts. Is there something I am missing on to why the pump relay will not work when plugged in? any info is appreciated.

DennisMik

iTrader: (2)

If you turn on the ignition, the relay will energize for about a second and then de-energize if you do not crank the engine. Do you know for certain if the relay never energizes for that initial one second?

Exactly what is your problem that has you looking at the relay?

RD Stephenson

The relay works. When hooked up to the battery it catches, however, when I plug the relay in it will not catch. getting power to the relay according to the reader, just wont engage when I have it plugged in.

DennisMik

iTrader: (2)

This is one of the most mis-diagnosed circuits in the car.

There are 4 pins on the bottom of the relay. They are numbered 1, 2, 3 and 5. Look on the bottom of the relay for tiny, tiny numbers. If you see a diagram on the top of the relay, DO NOT go by that.

To start with, you should always measure battery voltage (12 volts) on 2 of the 4 relay connections, specifically pins # 1 and 5. Pin 1 is for the electromagnetic coil in the relay that closes the contacts. Pin 5 is the power that will go to the fuel pump.

Power to pin 1 comes from fuse # 1. Power to pin 5 comes from fuse # 29.

The ECU puts a ground on pin 2 of the relay to energize the electromagnet coil and close the contacts. When the relay contacts close the 12 volts from fuse 29 comes out of the relay on pin 3.

As I stated previously, the relay will energize for about a second when you turn the ignition key on and then de-energize if you do not crank the engine. What keeps the relay energized is the ECU receiving pulses from the crankshaft flywheel sensor CKPS[POS].

Your responses are a bit vague, so I am not sure of exactly what you have discovered. Please use more detail.

maximatech12

What your going to have to do is get a multi-meter and get under the hood. use the multi-meter to run a few continuity tests around the related circuits.
one thing I picked up about relay switches is they usually either just blow out and dont work at all.