2000 Astro OBDII code po452

[roorufus]

Qiuck background:
2000 Astro, 189,000 miles. Was running, died, tried to restart and could not. First thought was fuel pump, however OBDII gives code Po452. From this we gathered something was telling the pump not to start or to shut down. When checking power to the pump, test light was VERY dim. Are there any common causes for this before we change every emission control item on the dumb thing? I am quite sure it is need of a fuel pump- it has been whining awhile, but the code is telling us the problem is before that.
HELP

[brcidd]

Your P0452 code has nothing to do with the fuel pump or fuel pump pressure-- is has everything do with the vapor/vacuum system of the fuel tank- sometimes just a loose gas cap can be the cultprit--
I would look elsewhere for the fuel pump input voltage problem- like at the relay or the oil pressure switch or even the fuse - or poor connections- instead of a test light - look at the amperage being pulled to run the pump-- how many amps-- should be around 8.5.........

here are the details of your code:

The fuel tank pressure (FTP) sensor responds to changes in the fuel tank pressure or vacuum. This information is used in order to detect vacuum decay or an excessive vacuum during the EVAP diagnostic routing. The fuel tank pressure sensor signal voltage to the vehicle control module (VCM) varies from a minimum of about 0.1 volts with pressure in the fuel tank to more than 4.0 volts with a high vacuum in the fuel tank.

The fuel tank pressure sensor display on the scan tool has an auto-zero feature which occurs at each ignition cycle and is corrected according to the barometric pressure. Because of this, the FTP sensor display may not accurately reflect the actual output of the sensor or the conditions within the fuel tank.

The FTP sensor diagnosis table is intended to isolate and diagnose the electrical problems with the sensor wiring or the sensor.

Conditions for Running the DTC
The ignition switch is in the RUN position.

Conditions for Setting the DTC
The fuel tank pressure sensor voltage is more than 0.1 volt for more than 5 seconds.

Action Taken When the DTC Sets
The VCM turns ON the malfunction indicator lamp (MIL) after 2 consecutive driving cycles with the fault active.

Conditions for Clearing the MIL or DTC
The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.
A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.
Use a scan tool in order to clear the DTCs.
Diagnostic Aids
Inspect the control module harness connectors for the following conditions:
- Improper mating

- Broken locks

- Improperly formed terminals

- Damaged terminals