No Power to Fuel Pump

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Aviation

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Car will crank but not start. Getting no power to the fuel pump. Cant hear it activate or anything when the key is turned.

What are the possibilities that could be causing this?

One thing I have heard, is the anti theft system being tripped and needing to be reset, or the chip in the key being bad, shutting off the fuel pump.

Anyone know the steps to reset this? Or must you get a dealer to do it? Im in the process of tracking down my spare key as well.

If it isnt the key or anti theft system, What else can it be? I'm going to get a fuel pump relay switch also just to test as well.
 
blown fuse or tripped cut off switch.

although, have you verified no power with a multimeter? its possible your pump is just dead.
 
Switch isnt tripped, I checked. And the fuse looked fine. Only thing related to that I havent looked at is the fuel pump relay.

And Yeah, no voltage reading at the fuel pump.

If it was the pump, wouldnt you still hear it come on, or have power going to it, even if it isnt working?

Or could a dead pump cause no power to come to the pump still?
 
Aviation said:
And Yeah, no voltage reading at the fuel pump.
Click to expand...

ok. its definitely a power issue then.


Aviation said:
If it was the pump, wouldnt you still hear it come on, or have power going to it, even if it isnt working?
Click to expand...

no, if the pump locked up or something, you wouldn't hear anything. you would have power still. just no pump.


Aviation said:
Or could a dead pump cause no power to come to the pump still?
Click to expand...

no, you would still have power.
 
okay yeah I thought I should still have power even if the pump was bad.

Another thing is, the code reader gave no codes, if that helps.
 
Whats the PATS light doing?

Try cycling the key a few times and holding the key in the start position.
 
Hawk03 said:
Whats the PATS light doing?

Try cycling the key a few times and holding the key in the start position.
Click to expand...

I think it stays on or blinks I cant remember off the top of my head., I will have to check for sure when I go home.
 
PATS would stop the starter from working.

The positive power to the fuel pump comes through the fuel pump relay, which is controlled by the REM. Relays and relay sockets in the trunk have been known to corrode and fail, especially if you are using a non-oem battery that is venting corrosive gases into the trunk.

The negative (ground) connection to the fuel pump motor comes from the REM and is electronically modulated to control the fuel pressure. I assume that you are checking the connections at the correct (electric) pump and not the jet (hydraulic) pump.
 
So, which side are you missing? The positive power to the pump, or the ground return to the pump?

If it's the positive, then is there power at the relay? What about the pump side of the relay? Is there power to the relay coil? Does the pump run (or at least get power) if you jumper between the two relay contacts?

If there's no power at the relay contacts, then check the impact cutoff switch. Maybe it's failed even though it is down. Basically, you have to trace all the way from the pump back to the battery. Somewhere between the two, you will find the break or fault in the circuit.
 
Okay, so I need to do the following...

1. Check to see if theres power at the relay thats in the trunk.

2. Check the pump side of the relay(relay coil)? <Not sure where this is located>

3. Check the pump cutoff switch, even though its down.<Its down and not popped up, how do I check if it is failed?>

4. Check to see if the pump runs by jumping the relay.

Thanks for the help so far. Just need some further explanation.
 
Aviation said:
...Thanks for the help so far. Just need some further explanation.
Click to expand...

That's not something I think I'll be able to do a good job of over the internet. Do you have a friend that is handy with a multimeter that could help you out? How did you determine there was no power at the fuel pump?
 
Yeah he had a meter to test the power at the fuel pump, but thats all that was tested. Im probably gonna have him help me look at it, just trying to get all my ducks in a row of everything to check.

Im just not sure where the relay coil on the pump side is, just where the relay is in the trunk.
 
Aviation said:
...Im just not sure where the relay coil on the pump side is, just where the relay is in the trunk.
Click to expand...

The relay coil is inside the relay. The question is, "is the relay being activated?" checking for voltage across the coil will answer that.
 
Read up a bit on relays. A relay is basically made up of two parts - a switch and a coil. When the coil is energized it pulls the switch.
So Joe is saying that there's a few areas to check in the trunk fuse box for the relay. With the key on, there should be power on two of the pins (one feeds the switch part, the other the coil), and other pin to the coil should have continuity to ground. That'll turn on the relay. Pop it back in and see if the power input to the pump is showing battery voltage.
Proceed from there.
Because of how the REM controls the pump, just checking for voltage across the fuel pump connector pins may not be accurate. Using a standard multimeter with any kind of PWM wave leads to significant confusion.
Honestly, you'd be best off having someone lend a hand.
 
oddball said:
Read up a bit on relays. A relay is basically made up of two parts - a switch and a coil. When the coil is energized it pulls the switch.
So Joe is saying that there's a few areas to check in the trunk fuse box for the relay. With the key on, there should be power on two of the pins (one feeds the switch part, the other the coil), and other pin to the coil should have continuity to ground. That'll turn on the relay. Pop it back in and see if the power input to the pump is showing battery voltage.
Proceed from there.
Because of how the REM controls the pump, just checking for voltage across the fuel pump connector pins may not be accurate. Using a standard multimeter with any kind of PWM wave leads to significant confusion.
Honestly, you'd be best off having someone lend a hand.
Click to expand...

A nice way of saying, dont try it yourself my man you have no idea! lol

Thanks for the explanation, I am having someone lend a hand. Just trying to put together a check list of sorts for when he does help to have a game plan of what to check, ya know?
 
I did already replace the relay though, so it either has to be the pump itself, or the wiring that goes to the pump, correct?
 
Yes, that's basically the test.
No, there's still the possibility of it being the REM.
There's no need to keep speculating. Some simple tests will narrow it down. Trying to outline them all at once isn't going well, so lets try this. One thing at a time.

1. Is +12V power present at the fuel pump when the key is first turned on or when cranking? (Measure between the +pwr pin to the pump and a bare metal ground somewhere nearby. Do not measure between the positive and negative pump power connections.)
 
Alright thank you. When I borrow a multimeter I will do this first test and post the results.
 
Which wire is the + power to the fuel pump? theres 4 wires...2 gray wires....green wire with stripe and white wire with stripe
 
On the passenger's side.

Green with orange band is the positive power to the fuel pump. (pin 2)
Black with red band is the negative power to the fuel pump. (pin 4)

White with red band is the feed to the fuel level sender. (pin 1)
Brown with red band is the ground to the fuel level sender. (pin 3)

On the driver's side.

White with blue band is the feed to the fuel level sender. (pin 1)
Brown with blue band is the ground to the fuel level sender. (pin 3)
 
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