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2001 Blazer P0452 Code: Evaporative Emission System Pressure Sensor/Switch Low Input - Diagnosis and Fix

Model: 2001 Blazer Fault Code: P0452 Posted: 2007-05-19 14:22

I'm experiencing a P0452 diagnostic code on my 2001 Blazer, which indicates a low input signal from the Evaporative Emission System Pressure Sensor or Switch. Is this a common issue? Can it be fixed easily, and where is the sensor located? Thanks for any advice!

Related fault codes
P0452
Comments (11)
Anonymous 2007-05-19 18:30

The P0452 code typically points to a low voltage reading from the Fuel Tank Pressure (FTP) sensor. While it's not an extremely difficult component to access, it can be tricky due to its location inside the fuel tank. Wiring issues are also possible. First, check for blown fuses or short circuits in the related circuit—this can help identify wiring faults before replacing parts.

Anonymous 2007-05-19 23:29

Thanks for the input! This is actually one of the last components I haven't addressed. I recently replaced the fuel pump myself, and after that, my truck stopped running completely. It was towed to a dealership, which diagnosed a faulty fuel pump. After replacing it myself, this P0452 code appeared.

Anonymous 2007-05-20 17:52

The Fuel Tank Pressure (FTP) sensor is typically located inside the fuel tank. If you're unsure of its position, consider asking the dealership to inspect it during a service visit—this could save time and prevent further issues.

Anonymous 2007-05-20 18:02

Could this issue be related to how the fuel pump was disconnected or reconnected during my repair?

Anonymous 2007-05-21 07:37

Yes, it's worth having the dealership review their work. Sometimes, improper installation or wiring errors can lead to unexpected codes even after a component replacement.

Anonymous 2007-05-21 08:11

The dealership isn't liable because you performed the fuel pump replacement yourself.

Anonymous 2007-05-21 10:23

Ah, I didn’t see that detail earlier—thanks for clarifying. In that case, they aren’t responsible since the repair was done by the owner.

Anonymous 2007-05-21 17:23

Thanks everyone! The connections are all properly attached. This was a high-cost fuel pump—nearly $600, and much more at dealerships. I believe I’ve found it: there’s a black module mounted on top of the fuel pump. I have the old unit too, so I might try reusing that before buying another. It looks like I’ll need to drop the fuel tank again—this is now my third failed fuel pump replacement. The dealership confirmed it wasn’t a truck issue; they found no pressure problems. However, the truck starts fine when it runs, but sometimes cranks for a while before starting. Previously, it would fire right up upon key turn. I got this code from a friend using a diagnostic reader.

Anonymous 2007-05-22 07:50

Repeated fuel pump failures in 2001 Blazer models are often caused by fuel contamination, clogged filters or lines, or misdiagnosed wiring issues related to the fuel pump connector. Before replacing your new part, double-check these factors—some aftermarket pumps may not perform reliably.

Anonymous 2007-05-22 08:04

Agreed—there are many poorly made aftermarket electric fuel pumps available for this application; quality varies significantly.

Anonymous 2008-09-03 15:11

This was extremely helpful! My 1998 Blazer also showed the same P0452 code. I’ll check the sensor soon after fixing the issue and update with my results—thank you!