No power to the fuel pump

Tiny
IKE RAPHAEL
  • MEMBER
  • 2006 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 120,000 MILES
Aloha,
I have checked: koeo
No power to the fuel pump connector BLK/R wire.
Good Ground WHT/Blk wire

Cranking voltage to the connector is approximately 5+/- V.

Both relays are checked and good (JB under the hood and under the dash.

With the key off to on- I also feel the relays being energized.

C/B for the EFI 20 amp is good.

The pump runs when by-passed.

The blinking security lights goes out when the key is inserted into the ignition.

This car was in a front-end accident with some damage to the radiator support. The airbags did not deploy.

I am a do it yourselfer with some engine repair knowledge but at this point I'm out of ideas.
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Friday, October 29th, 2021 AT 2:22 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

First, I attached the wiring schematic below for the powertrain management circuits. I highlighted things related to the fuel pump.

You mentioned the fuse was good for the EFI. In addition to checking the fuse, did you also check for power to and from it? Here is a link showing how it's done:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Next, when the ignition key is in the run or start position, power is sent to the coil open relay under the dash on left side. The power is supplied via a black wire with a white tracer. When power is applied, the contact which sends power to the fuel pump actuates and sends power via a black wire with a red tracer to the pump.

What I need you to do is this. First, go to the coil open relay. Turn the key to run and check power to the black/white wire. If it is there, check the black/red wire out for power.

If you haven't checked the relay, switch it with one having the same part number to see if it changes things. Or here is a link that explains how to test a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

If there is power at the black/red wire and you don't get it at the pump, you must have a broken wire at some point.

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below. Note: the schematics had to be cut in half to make them readable for you. I did overlap them so you can follow from one to the next.
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Friday, October 29th, 2021 AT 9:42 PM
Tiny
IKE RAPHAEL
  • MEMBER
Thank you for responding. I will follow-up on your recommendations and get back with you. It may be several days.
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Saturday, October 30th, 2021 AT 8:25 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

First, you are very welcome. Let me know what you find. Hang in there. We'll get it figured out one way or another.

Take care,

Joe
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Saturday, October 30th, 2021 AT 9:36 PM
Tiny
IKE RAPHAEL
  • MEMBER
Hey Joe,

I got around to checking a few things. The open circuit relay GRN/RED has 12v power to the disconnected connector at the ECM which I assume means that there is power from the ignition switch from the BLK/WHT wire.
No power from the BLK/RED wire to the fuel pump connector (C/OPN Relay).
Since this vehicle was in a front-end accident, would the TVIP system be involved. I hooked up my OBDII with no code found. Thanks
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Sunday, November 21st, 2021 AT 9:17 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
The green/red wire to the PCM is needed. The PCM provides a chassis ground via that wire. If that is disconnected, the CO relay cannot be actuated to power the fuel pump. In other words, no power is being sent to the pump simply because there is no power to actuate the relay.

And yes, if there is power to the green/red wire, then the black/white wire from the ignition switch is working.

I believe we found the problem.

Why is that wire disconnected at the PCM?

Let me know it that takes care of the problem.

Take care,

Joe

See pic below. It is from the manufacturer's schematics. I highlighted the indicator for chassis ground. That is the green/red wire even though it isn't indicated.
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Monday, November 22nd, 2021 AT 6:51 PM
Tiny
IKE RAPHAEL
  • MEMBER
Thank you for responding. The GRN/RED wire to the ECM was disconnected to check for 12V and reinstalled. Still no power to the BLK/RED wire at the fuel pump with the wire harness reconnected to the ECM. Sorry for not being clear on my actions.
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Tuesday, November 23rd, 2021 AT 4:18 PM
Tiny
IKE RAPHAEL
  • MEMBER
Both relays have been tested and are working properly.
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Tuesday, November 23rd, 2021 AT 4:23 PM
Tiny
IKE RAPHAEL
  • MEMBER
BTW, where is the E1 connector in the engine bay right front to check for possible ground problem from the MREL?
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Tuesday, November 23rd, 2021 AT 4:28 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
If you remove the CO relay is power present to it?

Also, pic 1 shows EA1 and EB1 connector locations.

Let me know what you find.

Joe
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Tuesday, November 23rd, 2021 AT 6:00 PM
Tiny
IKE RAPHAEL
  • MEMBER
HI Joe,

This is where I'm at regarding the circuit open relay switch.
I have 12v at pins 1 and 2 (back probing the relay switch halfway in the connector) with 12 volts to the ECM (GRN/RED) wire and BLK/WHT wire from the ignition switch. I also have 12 volts at pin 5. Pin 3 is grounded. I jumped pins 3/5 and I got 12v power to the fuel pump connector (this is good) however the relay is not closing. I verified the condition of the relay, and it works as it should; I also swapped relays with a known good one. I'm wondering why the relay is not closing. Is it something from the ECM?

Thank you
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Saturday, November 27th, 2021 AT 1:53 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

It sounds like the ECM isn't providing a ground path. If it doesn't, the relay won't actuate. Take a look at my generic pic below. The + from the ignition switch to the relay must complete the circuit to the ground from the ECM. If that doesn't happen, the relay remains open.

The ECM (according to the schematic) should provide a chassis ground. You mentioned having the ECM disconnected to confirm power to the green/red wire and you have it. However, did you check for ground at the ECM on that pin?

Just as a check, ground the green wire at the ECM and see if the pump turns on. The ECM controls the pump by grounding. It's a theory at this point, but based on what you told me, that seems like the issue. If that is the problem, either the ECM has lost ground or the ECM is bad.

Let me know what I can do to help.

Take care,

Joe

See pic below.
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Saturday, November 27th, 2021 AT 9:34 PM

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