GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Seville 🢒 DTC 🢒 DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage

Object Number: 603358 Size: MF
Engine Controls Components
Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The fuel tank pressure sensor measures the pressure (or vacuum) in the fuel tank. The 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 EVAP system. If the PCM detects a signal voltage that is too low, DTC P0452 will set.

Conditions for Running the DTC

The ignition is on.

Conditions for Setting the DTC

The fuel tank pressure sensor voltage is less than 0.06 volt for at least 1 second.

Action Taken When the DTC Sets
    • The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
    • The PCM will store the conditions present when the DTC set as Freeze Frame and Fail Records data.
    • The PCM will disable the EVAP system.

Conditions for Clearing the MIL/DTC
    • The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

If the condition is intermittent, refer to Intermittent Conditions .

Test Description

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check ?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Is DTC P1639 also set?

--

Go to DTC P1639 5 Volt Reference 2 Circuit

Go to Step 3

3
  1. Turn ON the ignition with the engine OFF.
  2. Observe the fuel tank pressure display on the scan tool.

Does the scan tool indicate a fuel tank pressure less than the specified value?

0.10V

Go to Step 5

Go to Step 4

4
  1. Review and record the scan tool Fail Records information.
  2. Operate the vehicle within the Fail Records conditions.
  3. Monitor the scan tool Specific DTC Information for DTC P0452 until the test runs.

Does the scan tool indicate that DTC P0452 failed last test?

--

Go to Step 5

Go to Diagnostic Aids

5
  1. Turn OFF the ignition.
  2. Disconnect the fuel tank pressure sensor connector.
  3. Turn ON the ignition with the engine OFF.
  4. Connect the appropriate jumper between the 5V reference B and sensor signal circuits.
  5. Observe the fuel tank pressure sensor voltage on the scan tool.

Does the scan tool indicate a fuel tank pressure sensor voltage near the specified value?

5V

Go to Step 9

Go to Step 6

6
  1. Remove the jumper.
  2. Using a digital multimeter (DMM) , measure the voltage between the 5V reference B and sensor ground circuits.

Does the DMM indicate a voltage near the specified value?

5V

Go to Step 7

Go to Step 8

7
  1. Test the fuel tank pressure signal circuit for the following conditions:
    2. • An open.
    • A short to chassis or sensor ground.
    • Faulty terminal connections at the PCM.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

8
  1. Test the 5V reference circuit for the following conditions:
    2. • An open.
    • Faulty terminal connections at the PCM.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

9
  1. Test for poor terminal connections in the fuel tank pressure sensor harness connector.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

10

Replace the fuel tank pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Is the action complete?

--

Go to Step 12

--

11

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 12

--

12
  1. Review and record the scan tool Fail Records information.
  2. Clear the DTCs.
  3. Operate the vehicle within the Fail Records conditions.
  4. Monitor the scan tool Specific DTC Information for DTC P0452 until the test runs.

Does the scan tool indicate that DTC P0452 failed this ignition?

--

Go to Step 2

System OK