Code P0452

Did you clear the code after replacing the fuel tank pressure sensor?
If not, do so and if you did follow this test procedure.

P0452

Diagnostic Procedures

1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, monitor fuel tank pressure sensor reading. If fuel tank pressure sensor value is within -1.0 to 1.0 in. H2O, go to next step. If fuel tank pressure sensor value is not within -1.0 to 1.0 in. H2O, go to step 4.
3. DTC is intermittent. Check for additional DTCs set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see DIAGNOSTIC AIDS.
4. Turn ignition off. Disconnect fuel tank pressure sensor harness connector. Turn ignition on, engine off. Using DVOM, check voltage between fuel tank pressure sensor harness connector 5-volt reference voltage and ground circuit. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 6.
5. Turn ignition off. Using jumper wires, connect jumper between fuel tank pressure sensor 5-volt reference circuit at harness connector to sensor terminal. Connect jumper between sensor ground circuit at harness connector to sensor terminal. Turn ignition on, engine off. Using DVOM, check voltage between ground and sensor signal circuit. If voltage reading is 1.3-2.0 volts, go to step 13. If voltage reading is not 1.3-2.0 volts, go to step 11.
6. Check for open in fuel tank pressure sensor 5-volt reference circuit. If circuit is open, go to step 15. If circuit is okay, go to next step.
7. Check for short to ground in 5-volt reference circuit. If circuit is shorted, go to step 15. If circuit is okay, go to next step.
8. Check 5-volt reference circuit for poor terminal contact at VCM. If problem is found, go to step 15. If terminal connection is okay, go to next step.
9. Check for open in fuel tank pressure sensor ground circuit. If circuit is open, go to step 15. If circuit is okay, go to next step.
10. Check sensor ground circuit for poor terminal connection at VCM. If problem is found, go to step 15. If terminal connection is okay, go to step 16.
11. Check fuel pressure sensor signal for short to ground. If circuit is shorted, go to step 15. If circuit is okay, go to next step.
12. Check fuel pressure sensor signal terminal connection at VCM. If problem is found, go to step 15. If terminal connection is okay, go to step 16.
13. Check fuel tank pressure sensor for water intrusion, backed out terminal, improper terminal mating or poor terminal-to-wire connections. If problem is found, go to step 15. If sensor connections are okay, go to next step.
14. Replace fuel tank pressure sensor. After replacing sensor, go to step 17.
15. Repair circuit as necessary. After repairs, go to step 17.
16. Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
17. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2.
18. Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay.

Place one test lead of the ohmmeter on the fuel pressure sensor signal wire and the other test lead on a metal ground and check if that wire is grounded or showing continuity to ground. It should read infinite.

Continue on to step 12.

It should be a dark green wire at connector 2/pin 25.
Here is the wiring diagram.

5.2 volts is about 5 volts so, If voltage reading is about 5 volts, go to next step.

If the result for step 11 is ol, or in other words infinity that is ok, meaning that wire isn't shorted to ground. So, go to the next step 12.

This is what the manual says, so I would just try it, if the engine starts just ride it around for awhile.
If you need to program any of those items, here are the procedures.
Vehicle Driveability Computer Relearn Procedure (4.3L, 5.0L, 5.7L & 7.4L)
Manufacturer does not provide a specified computer relearn procedure for obtaining proper driveability. If vehicle battery was disconnected or Vehicle Control Module (VCM) was replaced, driving the vehicle will enable the VCM to perform a computer relearn procedure for obtaining proper driveability. Inform customer that driveability may differ from what they are accustomed to until the VCM completes the computer relearn procedure.
Password Learn Procedure For Anti-Theft System (5.0L, 5.7L & 7.4L)
Password learn procedure must be performed if Vehicle Control Module (VCM), passlock module or passlock sensor is replaced. A password is communicated between VCM and passlock module to provide engine operation. If VCM is replaced, the VCM must learn the password from the passlock module.
Attempt to start engine. Engine will start and then stall. After engine stalls, leave ignition on for 10 minutes. After engine stalls, the SECURITY indicator light will come on for 10 minutes and then go off. The SECURITY indicator light is located on upper right corner of instrument panel, just above battery charge indicator.
NOTE: Ensure battery is fully charged before proceeding. Performing this procedure will cause a Diagnostic Trouble Code (DTC) P1630 to be set in the VCM. It will be necessary to use scan tool to check for DTC P1630 when performing this procedure. Ensure steps are followed in correct order or procedure may need to be repeated.
After SECURITY indicator light goes off, turn ignition off for 30 seconds. Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off. After SECURITY indicator light goes off, turn ignition off for 30 seconds.
Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off or until DTC 1630 is set in VCM.
Turn ignition off for 30 seconds. Turn ignition on and wait 30 seconds. Attempt to start engine. If engine starts, password learn procedure is complete. Ensure DTC 1630 is cleared from VCM by turning ignition off for 30 seconds and then turning ignition on again. If DTC 1630 is not cleared from VCM, perform test procedures for DTC 1630 and repair as necessary. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
NOTE: DTC 1630 will be set in VCM as result of this procedure. DTC P1630 may be cleared from VCM by turning ignition off for 30 seconds and then turning ignition on again.
If engine does not start, ensure procedure was properly followed. If procedure was properly followed, check for any DTCs. If any DTCs exist, perform test procedures for specified DTC and repair as necessary. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
Electronically Erasable Programmable Read Only Memory (EEPROM) Programming (4.3L, 5.0L & 5.7L)
If Vehicle Control Module (VCM) was replaced, the EEPROM in the VCM must be programmed. If EEPROM is not programmed, a Diagnostic Trouble Code (DTC) will be set in the VCM.
Ensure battery is fully charged. Ensure cable is properly connected on Data Link Connector (DLC). Turn ignition on. Perform EEPROM programming using the Techline equipment manufacturer's instructions and latest software applicable for the vehicle model.
Once EEPROM is reprogrammed, Crankshaft Position (CKP) sensor variation learn procedure and password learn procedure for anti-theft system must be performed using proper procedure.
NOTE: If EEPROM programming fails, ensure all electrical connections on VCM are okay. Check Techline for latest software. If EEPROM programming still fails, replace VCM.
Once Crankshaft Position (CKP) sensor variation learn procedure and password learn procedure for anti-theft system are performed, perform powertrain On-Board Diagnostic (OBD) system check. See POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
Crankshaft Position (CKP) Sensor Variation Learn Procedure (4.3L, 4.8L, 5.0L, 5.3L, 5.7L, 6.0L & 7.4L)
Procedure must be performed if any of the following have been done:
EEPROM was reprogrammed.
If crankshaft position sensor was removed or replaced.
Vehicle Control Module (VCM) was replaced.
Install scan tool on Data Link Connector (DLC). Apply parking brake. Block rear wheels. Ensure hood is closed.
Place transmission in Park (A/T models) or Neutral (M/T models). Start engine and warm engine until engine coolant temperature is at least 150°F (65°C). Ensure all accessories are off.
Apply service brakes. With engine idling, use scan tool to select and enable CKP sensor variation learn procedure.
Gradually accelerate engine to 4000 RPM. Quickly release throttle to idle position once CKP sensor variation learn procedure is obtained and engine starts to decelerate. Once CKP sensor variation values are learned, the VCM will return engine control to the operator and engine will respond to throttle position.
CAUTION: Ensure throttle is quickly released to idle position once CKP sensor variation learn procedure fuel cut off is obtained and engine starts to decelerate.
If CKP sensor variation learn procedure was completed, turn ignition off for at least 15 seconds and remove scan tool. If CKP sensor variation learn procedure was not completed, a DTC P1336 should be stored in the VCM. Perform test procedures for DTC P1336 and repair as necessary. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

I think you should repeat the steps again and let me know the results of all them steps beginning with the result from step 12, cause I assume you went to step 16 right after 12.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help. Good work PATENTED_REPAIR_PRO

Cheers, Ken

Glad to hear it is fixed, good work.