I need your knowledge and experience to determine if this was a coincidence or if several parts failed at the same time.

A little background, the vehicle is a 2003 Blazer 2dr, 4.3, auto with 139,000 miles. It's been trouble free since purchased at 36,000 miles in Oct '05.

The fuel gauge has never been very accurate (I reset the trip odometer at each fill-up and can go 275-300 miles per tank). At each fill-up the gauge will register full, will still be at ½ tank at approximately 200 miles, but once the gauge gets to ¼ tank it drops very fast to empty. This is the reason I reset the odometer and refill the tank based on mileage.

Recently as I was leaving work I decided to fill the tank at about 250 miles simply because I didn't want to mess with it over the weekend. As I was pulling away from the pumps after refueling, I noticed the SES light was on (it wasn't on before filling the tank). I knew there was an Advance Auto parts store 1 block down the street so I stopped in to have someone scan for DTC. Now for the really weird part, as I was turning into the Advance parts store I noticed the fuel gauge had quit working and dropped to below the empty mark and the Low Fuel light was on (these were not on when I noticed the SES light was on at the gas station).

The DTC scan gave code P0452 which I researched as being the 'Fuel Tank Pressure Sensor'.

Now for the questions, is it just a coincidence that these all happened at the same time or do you think they are related to a common problem? Any ideas what that problem would be and the proper repair for it?

Sorry for the long-winded post but I wanted to give as much info as possible.

Thanks in advance for your help,
Mike

 

P0452 - Evaporative Emission Control System Pressure Sensor Low Input

You could have lost the ground to the fuel pressure sensor and fuel level sending unit. These all tie together in the rear splice pack, S102. Many have found this splice pack to be corroded and causing a whole host of problems.

 

Maybe the gas cap is bad?? No pressure can build if the cap is gone or loose or just not sealing. Just a thought.

 

Thank you very much for your help!! I'm well aware of how bad grounds cause the majority of electrical issues. What I'm not familiar with is the location of the S102 rear splice pack, can you also help with this?

Thanks again,
Mike

 

Actually, I just looked up the information specific to your truck and the wiring for the FTP sensor is different than the 01 & older models which is what was referred to in the link I provided. Your truck uses a low reference return to the PCM. This same low reference is what is used for the fuel level sending unit which tie together at S422. S422 is a splice inside the wiring harness and not a splice pack which would look like a dead ended connector.

You should test continuity from the blk/wht wires at both the FTP sensor and the fuel level sending unit to each other as well as to connector 1 (blue) pin 23 at the PCM. They all should show good continuity with very little resistance.

 

Your information is greatly appreciated, I'll check the wiring in the next few days (weather permitting) and let you know what I found.

Thanks,
Mike