Well I've read all the threads I could on this code and still have questions... I'm getn the P0452 CODE ftp sensor connector voltage low or circuit open... pcm failure I suppose due to the po452.? Not sure. I've got a 99 blazer 2dr 2wd 4.3 vortec. Sat up for 4 years before I got it running and now use as my daily driver.. 153k miles on her . She's my baby... I seem to have always had a sluggish start with acceleration when first cranked since ive had her.. ive cleaned tank and replaced fuel pump and filter. She has never given me a sec of prob when starting up... never she idles like a purring kitten. I've replaced the plugs/wires, alternator, starter, fuel pump and filter, oil and filter. Installed K&N cold air and Flowmaster exhaust system. Replaced. The a/c compressor too. Sorry bout the lengthy post but just tryin to let you know where I'm at.. When I replaced the fuel pump I did not replace the connector that came with it cuz the previous owner had already made the switch. Am I going to have to drop tank again and replace fuel pump?
It's still under warranty from rockauto.com
Please share the knowledge... thank you.

 

You have brought up multiple issues.


Do you have any other codes or just P0452?

Why do you think your PCM is damaged?

Why do you think that your fuel pump or it’s connector is damaged?

P0452 is related to your evap system which is charged with minimizing fuel vapors from escaping into the atmosphere. The system routinely tests the integrity of the hoses, valves, gas cap, and reports if there is a leak or an improper reading from a sensor. A pressure failure can be a loose gas cap, a leaking hose or canister, a failed valve, a failed sensor, a wiring/connector problem, and the least likely - a pcm failure. There is no involvement with the fuel pump and fuel pressure. An evap system failure rarely affects engine performance but may increase emissions and may cause an inspection failure. The biggest pita situation related to your evap system is when you can’t fill the gas tank at full pressure or if you fail inspection.

What problem are are you trying to solve: a fuel pump issue, an engine performance issue, or an evap code issue?


George

 

"An evap system failure rarely affects engine performance. "

Dont tell my 95 that...it idles very roughly when the evap system disconnected.

OP -guessing will not help. Dont remove the pump, thats just wild guessing, check the pressure.

 

Rarely but still possible. In the majority of cases here when there is an evap code there is no discussion of performance issues and a gas cap solves the problem. If you remove the purge valve or the associated hoses without capping off the access to the manifold and create a large vacuum leak then you would affect engine performance as perhaps you did. I am assuming that the OP has not removed his entire evap system and left the lines open. If the system is intact and the purge valve and line is still connected and closed as it normally is then any issues are in all the other hoses, cap, canister, evap solenoid, etc and throws codes but does not affect manifold pressure.

George

 

Thank you to all who replied. This is what I got I put my odb2 sensor reader on my blazer and this is what it says
Po452 po452..

FTP sensor connector is damaged or shorted.
FTP sensor signal circuit is open
FTP sensor signal circuit is open or shorted to ground
FTP sensor vref circuit is open or shorted to ground
FTP sensor is damaged or has failed
PCM has failed
Fuel tank pressure sensor circuit low voltage
This is what I've got on my odb2 reader scanner
I hope this answers some of y'all's questions about why I asked what I asked I'm still having the check engine light on I can clear it it comes right back on if y'all can give me the answers from this data please do I'm recording live data in the DTC trigger mode right now I'll let you know what I get to follow thank you

 

You need to check the wiring and connector to the sensor as well as confirm a good clean 5V level on the 5V reference wire (gray) at the sensor. Keep in mind that this sensor uses a signal ground, not chassis ground so checking continuity on the signal and signal ground wire has to go back to the PCM.

Good news is that this is a $30 sensor if that is the problem.

George