For 1990-2009 cars
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 fuel tank pressure 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 above 4.0 volts with a high vacuum in the fuel tank.

The fuel tank pressure 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 fuel tank pressure may not accurately reflect the actual output of the sensor or the conditions within the fuel tank.

### 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 malfunction indicator lamp (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 Powertrain Control Module (PCM) harness electrical connectors for the following conditions:

- | Improper mating

- | Broken locks

- | Improperly formed

- | 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.

Refer to Evaporative Emission System Cleaning before starting repairs.

### Test Description

Numbers below refer to the step numbers on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.

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

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

• | PCM

• | Fuel Tank Pressure sensor 5.0 V reference circuit

• | Fuel Tank Pressure sensor signal circuit

4. This step looks for an open in the Fuel Tank Pressure sensor ground circuit.

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

6. Important: The Powertrain Control Module (PCM) uses a single 5.0 volt power supply to supply power to all the engine control components. If one component shorts its 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. Check and repair any circuit or replace any sensor that may have caused the short on the 5.0 volt reference circuit.

7. Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM programming and Crankshaft Position System Variation Learn .

#### DTC P0453-Fuel Tank Pressure Sensor Circuit-High Voltage

Step | Action | Value(s) | 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 |

1. Disconnect the vapor line from the fuel tank at the EVAP canister.
2. Install a scan tool.
3. Turn ON the ignition switch leaving the engine OFF.

Does the scan tool display a Fuel Tank Pressure value of the specified value or more?

3.0 V

Go to Step 3

Go to Step 4

3 |

1. Turn OFF the ignition switch.
2. Disconnect the Fuel Tank Pressure sensor electrical connector.
3. Turn ON the ignition switch leaving the engine OFF.

Does the scan tool display a Fuel Tank Pressure value of the specified value or less?

0.2 V

Go to Step 5

Go to Step 6

4 |

1. Turn OFF the ignition switch.
2. Reconnect the vapor line from the fuel tank to the EVAP canister.
3. Turn ON the ignition switch leaving the engine OFF.
4. Review the Freeze Frame data and note the parameters.
5. Start the engine.
6. Operate the vehicle within the freeze frame conditions and Conditions For Setting The DTC as noted.

Does the scan tool display a Fuel Tank Pressure value equal to or greater than the specified value?

3.0 V

Go to Step 3

Go to Diagnostic Aids

5 |

1. Connect a test light to battery voltage.
2. Probe the Fuel Tank Pressure sensor ground circuit terminal.

Does the test light illuminate?

--

Go to Step 7

Go to Step 9

6 |

1. Check the Fuel Tank Pressure sensor signal circuit for a short to voltage.
2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 12

Go to Step 10

7 |

1. Connect a DMM to ground.
2. Probe the Fuel Tank Pressure sensor 5.0 volt reference circuit.

Does the DMM display near the specified value or less?

5.0 V

Go to Step 11

Go to Step 8

8 | Important: The Powertrain Control Module (PCM) uses a single 5.0 volt power supply to supply power to all the engine control components. If one component shorts its 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.

1. Disconnect the PCM electrical connector.
2. Check the Fuel Tank Pressure sensor 5.0 volt reference circuit for a short to voltage.
3. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 12

Go to Step 10

9 |

1. Turn OFF the ignition switch.
2. Check for the following conditions in the Fuel Tank Pressure sensor ground circuit:

• | Open circuit

• | Poor electrical terminal connection at the PCM.

3. Repair the connection as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 12

Go to Step 10

10 |

1. Check the PCM electrical connector terminals for being clean and tight.
2. If OK, replace the PCM. Refer to the Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 12

--

11 |

1. Turn OFF the ignition switch.
2. Check the Fuel Tank Pressure sensor electrical connector terminals for being clean and tight.
3. If OK, replace the Fuel Tank Pressure sensor. Refer to the Fuel Tank Pressure Sensor Replacement .

Is the action complete?

--

Go to Step 12

--

12 |

1. Reconnect the vapor line from the fuel tank to the EVAP canister.
2. Turn ON the ignition switch leaving the engine OFF.
3. Using the scan tool, clear the DTCs.
4. Start the engine and idle at normal operating temperature.
5. Operate the vehicle within the conditions for setting this DTC as supported in the text.

Does the scan tool indicate that this diagnostic ran and passed?

--

Go to Step 13

Go to Step 2

13 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK