No power to fuel pump

Tiny
PDBLM
  • MEMBER
  • 2002 FORD MUSTANG
I have power to inertia switch if fpdm is unplugged, when plugged in power is lost. What are the lt/bl & wt/rd wires from fpdm. Pump runs when jumped so no it's not bad. Tryed new fpdm, same problem. I have 6.04 volts on light blue/ orange wire. Have nothing on white/red wire
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Wednesday, May 29th, 2013 AT 11:32 AM

6 Replies

Tiny
HMAC300
  • EXPERT
Lt blue and white/red go to pcm it may be abad module why you loose power to inertia switch. I'm sending a pic along. Try cleaning the ground for the module at left rear of car. The white red wire may not have anything only at certain times or the module Is bad. Scan it and see if anything pops up.
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Wednesday, May 29th, 2013 AT 12:43 PM
Tiny
HMAC300
  • EXPERT
The inertia switch is supplied by the fuel pump relay it should be a dk/grn/yell wire going to switch with a pinkblk going out. That goes to a module that then powers the pump. (Pic shown of module/pump.) It cold be a bad module. Or an inertia switch that causes your power loss whe nteh fp what ever the hell connection you are talking about is plugged in. The ltblue and red both go to the pcm. One may be power and the othe maybe return to show module is activated in pcm.
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Wednesday, May 29th, 2013 AT 12:44 PM
Tiny
PDBLM
  • MEMBER
Fpdm is fuel pump drive module. Already replaced, no change. How much voltage should be coming from pcm to module? On the light blue/orange wire I have 6.04 volts.
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Thursday, May 30th, 2013 AT 9:21 AM
Tiny
PDBLM
  • MEMBER
I also got dtc fuel pump drive module offline
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Thursday, May 30th, 2013 AT 9:23 AM
Tiny
HMAC300
  • EXPERT
Connect a jumper wire between the FPDM PWR (VPWR for Continental) pin and FP PWR pin at the FPDM harness connector.
Key on.
Measure voltage between the FP PWR circuit at the fuel pump harness connector and the battery negative post.
Is voltage greater than 10.5 volts, AND within 0.5 volt of the reading in KB72?

Yes No
KEY OFF. REMOVE jumper. VERIFY previous test steps. CHECK related connectors for corrosion, etc. If all checks are OK, REPLACE FPDM. KEY OFF. REMOVE jumper. CHECK for causes of high resistance in FP PWR circuit.

KB75 CHECK B+ TO ELECTRONIC ENGINE CONTROL (EC) POWER RELAY (CONTINENTAL), CCRM OR FPDM POWER SUPPLY RELAY
Disconnect CCRM (Escort, Mustang), electronic EC power relay (Continental) or FPDM power supply relay (all others).
Key on (to put same load on battery as previous steps).
For Escort, Mustang:
Measure voltage between pin 11 (B+) of the CCRM harness connector and the battery negative post.
For Continental:
Measure voltage between the B+ circuit at the electronic EC power relay harness connector and the battery negative post.
For all others:
Measure voltage between the B+ circuit at the FPDM power supply relay harness connector and the battery negative post.
Is voltage greater than 10.5 volts?
Yes No
KEY OFF. GO to KB76. Improper voltage is being supplied to the CCRM, FPDM power supply relay or electronic EC power relay. CHECK associated wiring, connectors, etc. REPAIR as necessary.
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Thursday, May 30th, 2013 AT 9:37 AM
Tiny
HMAC300
  • EXPERT
Try those first two steps I forgot the pic on where to put jumper it's on this reply.
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Thursday, May 30th, 2013 AT 9:38 AM

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