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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 DeVille 🢒 DTC 🢒 DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage

Object Number: 604192 Size: MF
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OBD II Symbol Description Notice
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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 conditions which were 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

Notice: Use the connector test adapter kit J 35616-A for any test that requires probing the following items:

   • The PCM harness connectors
   • The electrical center fuse/relay cavities
   • The component terminals
   • The component harness connector
Using this kit will prevent damage caused by the improper probing of connector terminals.

Check for the following conditions:

    • Poor connections at the PCM and the fuel tank pressure sensor--Inspect the harness connectors for backed out terminals, improper mating broken locks, improperly formed or damaged terminal, and poor terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • 
        Damaged harness--Inspect the wiring harness for damage. Refer to Wiring Repairs in Wiring Systems.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.

Step

Action

Values

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

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 switch with the engine OFF.
  2. Observe the fuel tank pressure display on the scan tool.

Does the scan tool indicate a fuel tank pressure within the specified values?

get values

Go to Step 4

Go to Step 5

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 this ignition?

--

Go to Step 5

Go to Diagnostic Aids

5
  1. Turn OFF the ignition switch.
  2. Disconnect the fuel tank pressure sensor connector.
  3. Turn ON the ignition switch, with the engine OFF.
  4. Connect the appropriate jumper between the 5V Reference B and sensor ground 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 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. Check the fuel tank pressure signal circuit for the following conditions:
    2. • An open
    • A short to chassis or sensor ground
    • Poor terminal connections at the PCM, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 12

Go to Step 11

8
  1. Check the 5V Reference circuit for the following conditions:
  2. An open
  3. Poor terminal connections at the PCM, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  4. If a problem is found, repair as necessary. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 12

Go to Step 11

9
  1. Check for poor terminal connections in the fuel tank pressure sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 12

Go to Step 10

10

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

Is 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 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