Fuel Pump Driveway Diagnosis

Posted by Power Probe TEK on December 4th, 2018
Categories : Blogs
Early Saturday morning I heard my roommate trying to start her car, unfortunately it wasn’t starting. She asked me if I could help her out. I am an automotive technician, but I don’t have a lot of tools at my house, however; I do have my Power Probe 3 circuit tester.
My roommate told me she just spent a bunch of money to have her fuel pump replaced and she wasn’t happy she is still having a problem.
Since I verified the issue of a crank and no start, I wanted to check if the problem was fuel related. I had my roommate turn the key on while I listened for the fuel pump to come on, which it did not.
My next step was to look at the schematic for her 2001 Honda accord 2.3 Liter.

Main Relay Diagram
I found out that the Fuel Pump is controlled by the PCM through the PGM-FI Main Relay. Upon reading ProDemand, I found out that the Main Relay is a common failure on this vehicle. The relay isn’t cheap and since my roommate already spent a lot of money on her fuel pump, I want to make sure that this is the issue.
First: I checked the fuse. I can’t tell you how many times I’ve encountered an electrical issue only to find out that the fuse was blown!

Driver Side Fuse Panel
I located the Fuel Pump fuse on the driver’s side fuse panel. My Power Probe 3 showed there was power going to the both sides of the fuse with the key on, so the fuse tests good.
My next step was to test the relay. The relay has six pin outs (one BLK/YEL, two BLU/ORG, one RED/WHT, and two BLK/YEL) found in the Relay box underneath the driver’s side dash, near the steering column. I was able to verify that the relay had all the correct voltages going to it. I went to one of the BLK/YEL terminals, and using my Power Probe, I applied 12 volts directly to the Fuel Pump to see if it turns on and it does. All signs pointed to the Fuse Relay Box. After purchasing a Fuse Relay Box from a local Auto Parts Store, I installed it and the vehicle started! Having to fix my roommates car was not the way I wanted my Saturday would start, but at least my roommate is happy!

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