GM Service Manual Online
For 1990-2009 cars only

Object Number: 621239  Size: SF
Engine Controls Components
Engine Data Sensors
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The fuel tank pressure sensor is used in order to detect a vacuum decay or an excessive vacuum during the EVAP diagnostic routine. The sensor responds to the changes in the fuel tank pressure or vacuum. The signal voltage to the Powertrain Control Module (PCM) varies from a minimum of about 0.2 volts with pressure in the fuel tank to more than 4.0 volts with a high vacuum in the fuel tank.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The fuel tank pressure sensor voltage is more than 4.9 volts for more than 25 seconds.

Action Taken When the DTC Sets

    • The malfunction indicator lamp (MIL) will illuminate.
    • The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.
    • A history DTC stores.

Conditions for Clearing the MIL/DTC

    • The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault.
    • A history DTC will clear after 40 consecutive warm up cycles without a fault.
    • Use a scan tool to clear the DTCs.

Diagnostic Aids

Check for the following conditions:

    • Inspect the PCM harness electrical connectors for the following conditions:
       - Any incorrect mating
       - Any broken locks
       - Any incorrectly formed terminals
       - Any damaged terminals
    • Inspect the wiring harness for damage. If the harness appears to be OK, observe the Fuel Tank Pressure display on the scan tool while moving the electrical connectors and the wiring harnesses related to the sensor. A change in the display will indicate the location of the malfunction.

Test Description

Numbers below refer to the step numbers on the diagnostic table.

  1. This step will determine if DTC P0453 is the result of a hard malfunction or an intermittent condition.

  2. This step simulates the conditions for DTC P0452. If the PCM recognizes the change, that indicates that the following items are OK:

  3. • The PCM
    • The 5.0 V reference circuit for the fuel tank pressure sensor
    • The signal circuit for the fuel tank pressure sensor
  4. This step looks for an open in the sensor ground circuit.

  5. When the sensor signal circuit is shorted to battery voltage, the TP will be displayed above 0 percent at all times and the A/C High Side will be displayed high. The vehicle will also remain in Open Loop.

  6. Important: The PCM uses a single 5.0 volt power supply to supply power to all the engine control components. If one component shorts the 5.0 volt reference circuit to ground or battery voltage, the other 5.0 volt reference circuits will also have a low or high voltage.

    Disconnect all the sensors that use a 5.0 volt reference one at a time while monitoring the short on the 5.0 volt reference circuit. Repair any circuit or replace any sensor that may have caused the short on the 5.0 volt reference circuit.

  7. The replacement PCM must be programmed and the Crankshaft Position System Variation Learn procedure must be performed.

DTC P0453-Fuel Tank Pressure Sensor Circuit-High Voltage

Step

Action

Value(s)

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

Operate the vehicle within the Freeze Frame conditions and the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 3

Go to Diagnostic Aids

3

  1. Disconnect the fuel tank vapor line at the EVAP canister.
  2. Turn on the ignition, leaving the engine off.
  3. With a scan tool, observe the Fuel Tank Pressure sensor.

Is the pressure more than or equal to the specified value?

4.9 V

Go to Step 4

--

4

  1. Turn off the ignition.
  2. Disconnect the fuel tank pressure sensor.
  3. Turn on the ignition, leaving the engine off.

Is the pressure less than or equal to the specified value?

0.2 V

Go to Step 5

Go to Step 6

5

  1. Connect a test lamp to battery voltage.
  2. Probe the sensor ground circuit.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 9

6

  1. Test the sensor signal circuit for a short to voltage.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

7

  1. Connect a DMM to ground.
  2. Probe the sensor 5 volt reference circuit.

Does the voltage approximately equal the specified value?

5 V

Go to Step 10

Go to Step 8

8

Important:: The PCM uses a single 5 volt power supply to all the engine control components. If one component shorts the 5 volt reference circuit to battery voltage, the other 5 volt reference circuits will also have a high voltage.

  1. Test the sensor 5 volt reference circuit for a short to voltage.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

9

  1. Turn off the ignition.
  2. Test the sensor ground circuit for the following conditions:
  3. • An open
    • Any poor connections
  4. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

10

  1. Inspect the sensor circuit for poor connections.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

11

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

Did you complete the repair?

--

Go to Step 13

--

12

Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the repair?

--

Go to Step 13

--

13

  1. Use a scan tool to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK