Phrog_gunner
09-05-2009, 07:53 PM
If you don't want to hear my background story you can skip straight to "Troubleshooting Steps" below....
I recently tried to start my car only to find that the fuel pump did not come on. I knew there was a fuse, relay and fuel pump shut off switch to check. I searched the forum for anything else that I might be missing, and had read threads till my eyes were tired and came to the conclusion it had to be my fuel pump. I worked in auto parts for nine years and RARELY sold electric fuel pump. They are very reliable and it just didn't sit right with me that mine went bad at under 50k miles, especially after reading about several other members replacing their pumps so recently. After getting two estimates close to $900, I decided to search the forum again out of sheer cheapness. After tons more searching I came across a thread about fuel pressure that mentioned a fuel pump driver module. This wound up being my problem, but this was the only thread that it had been mentioned in after all of the fuel pump threads I had seen. In fact I had a hard time finding that thread when I decided to write this. Since a fuel pump is such an expensive replacement and the troubleshooting steps can by done by anyone in about a half hour, I decided to write this so it's all in one place and so you can hopefully find the problem yourself without paying the dealers $120 diagnostic fee. You will also know that all of the easy things are working and it really is a major problem keeping your car from starting.
TROUBLESHOOTING STEPS:
This guide is only intended to troubleshoot a fuel pump that does not run at all (no noise heard when the key is turned on), not a possible fuel pressure issue caused by the fuel pump. The steps are in order of easiest to hardest to complete and only cover the components not wiring. After each step I turned the ignition to the on position to listen for the fuel pump.
1. Fuel Pump Shut-off Switch. This switch is in the trunk on the left side. Try to push the red button down. If it can be pushed down you will feel it click, and your car will probably start right away. Mine had not popped up but I gave mine a firm tap with the handle of the screwdriver to make it pop up in case of a bad connection. Then I pushed the button back down. At this point I also made a jumper wire and jumped the only two wires on the connector to the switch. In hindsight, I wouldn't try this until after step 4 because fuses are much more likely to be bad and you will be making jumper wires in step 4 anyway.
2. Fuel Pump Fuse. This is a 20A fuse in position 5 in the power distribution box in the engine compartment right behind the battery. In the past I have seen a fuse not work even though it didn't look blown so I swapped the #5 fuse with the 20A fuse in position #2. This fuse is for one of the power points so it won't keep the engine from starting if we wind up moving around a bad fuse.
3. Fuel Pump Relay. This relay is in position #203 in the power distribution box. I swapped this relay with the identical relay in position #201. This is the horn relay so once again we won't wind up swapping a bad relay into a position that would also keep the engine from starting.
4. Fuel Pump Driver Module. This module is located in the trunk directly below the fuel pump shut off switch. To get to this module, remove the piece of carpeting on the left side of the trunk that covers the fuel pump shut off switch. This is the only part (besides a CD changer) in the area so once the carpet is out you are looking right at it. It has a 10 pin connector. I took two short pieces of wire to use as jumpers. Jump pin 9 (white, HOT wire) to pin 10 (pink/black). Then jump pin 2 (black, ground) to pin 3 (brown/white). When I turned the key this time I heard the sweet sound of saving $900 aka my fuel pump. Bypassing the module in this method causes the fuel pump to run full blast, so should only be used minimally to keep from damaging components. The module has one bolt at the top that holds it on and it takes more time to get the carpet off and on than it does to change the module.
I grabbed one out of the bone yard for the low low price of $5.34. The factory part number is 3W1F-9D372-AB. I pulled mine out of an '05 CV, but the '00 CV I checked did not come with one of these modules from the factory so try to keep as close to our model years as possible to speed up your search.
To the best of my knowledge, the only thing left after these components to check is the fuel pump itself and the wiring. If anyone with the factory manuals know of anything I missed, please correct me. If this keeps one person from paying $700-$800 for a fuel pump install because of this apparently little known module, then it is worth it.
I recently tried to start my car only to find that the fuel pump did not come on. I knew there was a fuse, relay and fuel pump shut off switch to check. I searched the forum for anything else that I might be missing, and had read threads till my eyes were tired and came to the conclusion it had to be my fuel pump. I worked in auto parts for nine years and RARELY sold electric fuel pump. They are very reliable and it just didn't sit right with me that mine went bad at under 50k miles, especially after reading about several other members replacing their pumps so recently. After getting two estimates close to $900, I decided to search the forum again out of sheer cheapness. After tons more searching I came across a thread about fuel pressure that mentioned a fuel pump driver module. This wound up being my problem, but this was the only thread that it had been mentioned in after all of the fuel pump threads I had seen. In fact I had a hard time finding that thread when I decided to write this. Since a fuel pump is such an expensive replacement and the troubleshooting steps can by done by anyone in about a half hour, I decided to write this so it's all in one place and so you can hopefully find the problem yourself without paying the dealers $120 diagnostic fee. You will also know that all of the easy things are working and it really is a major problem keeping your car from starting.
TROUBLESHOOTING STEPS:
This guide is only intended to troubleshoot a fuel pump that does not run at all (no noise heard when the key is turned on), not a possible fuel pressure issue caused by the fuel pump. The steps are in order of easiest to hardest to complete and only cover the components not wiring. After each step I turned the ignition to the on position to listen for the fuel pump.
1. Fuel Pump Shut-off Switch. This switch is in the trunk on the left side. Try to push the red button down. If it can be pushed down you will feel it click, and your car will probably start right away. Mine had not popped up but I gave mine a firm tap with the handle of the screwdriver to make it pop up in case of a bad connection. Then I pushed the button back down. At this point I also made a jumper wire and jumped the only two wires on the connector to the switch. In hindsight, I wouldn't try this until after step 4 because fuses are much more likely to be bad and you will be making jumper wires in step 4 anyway.
2. Fuel Pump Fuse. This is a 20A fuse in position 5 in the power distribution box in the engine compartment right behind the battery. In the past I have seen a fuse not work even though it didn't look blown so I swapped the #5 fuse with the 20A fuse in position #2. This fuse is for one of the power points so it won't keep the engine from starting if we wind up moving around a bad fuse.
3. Fuel Pump Relay. This relay is in position #203 in the power distribution box. I swapped this relay with the identical relay in position #201. This is the horn relay so once again we won't wind up swapping a bad relay into a position that would also keep the engine from starting.
4. Fuel Pump Driver Module. This module is located in the trunk directly below the fuel pump shut off switch. To get to this module, remove the piece of carpeting on the left side of the trunk that covers the fuel pump shut off switch. This is the only part (besides a CD changer) in the area so once the carpet is out you are looking right at it. It has a 10 pin connector. I took two short pieces of wire to use as jumpers. Jump pin 9 (white, HOT wire) to pin 10 (pink/black). Then jump pin 2 (black, ground) to pin 3 (brown/white). When I turned the key this time I heard the sweet sound of saving $900 aka my fuel pump. Bypassing the module in this method causes the fuel pump to run full blast, so should only be used minimally to keep from damaging components. The module has one bolt at the top that holds it on and it takes more time to get the carpet off and on than it does to change the module.
I grabbed one out of the bone yard for the low low price of $5.34. The factory part number is 3W1F-9D372-AB. I pulled mine out of an '05 CV, but the '00 CV I checked did not come with one of these modules from the factory so try to keep as close to our model years as possible to speed up your search.
To the best of my knowledge, the only thing left after these components to check is the fuel pump itself and the wiring. If anyone with the factory manuals know of anything I missed, please correct me. If this keeps one person from paying $700-$800 for a fuel pump install because of this apparently little known module, then it is worth it.