Circuit Description
The fuel tank pressure sensor measures the pressure, or vacuum, in the fuel tank. The powertrain control module (PCM) provides the sensor with a reference voltage, a signal circuit, and a ground. The sensor returns a signal voltage to the PCM relative to the pressure in the fuel tank. The PCM should see a signal voltage increase as the pressure in the tank decreases (more vacuum). As the pressure in the tank increases (less vacuum), the PCM should see a signal voltage decrease. The PCM uses the sensor signal to test the integrity of the evaporative emission (EVAP) system. If the PCM detects a signal voltage that is too high, DTC P0453 will set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The fuel tank pressure sensor voltage is more than 4.9 volts for at least 1 second.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 | Is DTC P1639 also set? | -- | Go to DTC P1639 | Go to Step 3 |
3 | Is DTC P0463 also set? | -- | Go to Step 4 | Go to Step 6 |
4 |
Is the test lamp ON? | -- | Go to Step 5 | |
5 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 12 |
6 |
Does the scan tool indicate a fuel tank pressure above the specified value? | 4.7 V | Go to Step 8 | Go to Step 7 |
Does the scan tool indicate that this DTC reset? | -- | Go to Step 8 | Go to Intermittent Conditions | |
8 |
Does the scan tool indicate a fuel tank pressure sensor voltage near the specified value? | 0 V | Go to Step 11 | Go to Step 9 |
9 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 8 |
11 | Replace the fuel tank pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement . Is the action complete? | -- | Go to Step 13 | -- |
12 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 10 | -- |
13 |
Does the DTC run and pass? | -- | Go to Step 14 | Go to Step 2 |
14 | With a scan tool, observe the stored information, Capture info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
