Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptor
DTC P0454: Fuel Tank Pressure (FTP) Sensor IntermittentDiagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
FTP Sensor Low Reference | -- | P0446, P0451 | P0446 | -- | P0451 |
FTP Sensor Signal | P0452 | -- | P0452 | P0453 | P0451, P0454 |
FTP Sensor 5-Volt Reference | P0452, P0530, P0641 | P0451 | P0446, P0452 | P0453, P0530, P0641 | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
FTP Sensor Low Reference | -- | 1.5 V | 4.6 V | -- |
FTP Sensor Signal | 1.5 V | 0 V | 0 V | 5 V |
FTP Sensor 5-Volt Reference | -- | 0 V | 0 V | 5 V |
¹ With EVAP system vented to atmosphere | ||||
Circuit/System Description
The fuel tank pressure (FTP) sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. The controller also uses this FTP signal to determine atmospheric pressure for use in the engine-off small leak test, DTC P0442. This DTC is designed to detect an intermittent signal from the FTP sensor that would prevent the engine take-off small leak test, DTC P0442, from running.
Conditions for Running the DTC
| • | DTC P0454 runs only when the engine-off natural vacuum small leak test, P0442, executes. |
| • | This test can run once per engine-off period. The length of the test can be up to 10 minutes. |
| • | A refueling event is not detected. |
Conditions for Setting the DTC
If, during the engine-off natural vacuum small leak test, P0442, the engine control module (ECM) detects an abrupt FTP signal change, other than a refueling event, this DTC will set. An abrupt change is defined as a change of 1 inch H2O in the span of 1 second.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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. |
Diagnostic Aids
| • | This diagnostic is designed to detect an unexpected abrupt voltage signal change from the FTP. |
| • | Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To look at the sensor signal under vacuum conditions, use snapshot and the purge/seal function to capture data while commanding purge to 30 percent, and then plot the data to look for erratic sensor operation. A similar inspection can be done for the pressure side of the sensor range by applying pressure with the J 41413-200 while taking a snapshot. |
| • | Ensure that the reference port on the FTP sensor is unobstructed. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Special Tools Required
J 41413-200 Evaporative Emission System Tester (EEST)
Circuit/System Verification
- If DTCs P0452, P0453, or P0641 are set, repair those first.
- With a scan tool, command the EVAP canister vent solenoid valve closed.
- Command the purge solenoid to 30 percent.
- Observe the FTP sensor voltage parameter as the vacuum increased to the abort limit.
- The voltage should scale smoothly.
Circuit/System Testing
- Start the engine with the J 41413-200 connected to the fuel filler neck.
- Allow the engine to idle.
- Use the Purge/Seal function to seal the system with a scan tool.
- Command the EVAP canister purge solenoid valve to 30 percent.
- Observe the vacuum/pressure gage on the J 41413-200 and the FTP parameter on the scan tool.
- Allow the vacuum to increase on the gage of the J 41413-200 until it reaches approximately 16 inches H2O, or until the vacuum reached the abort limit on the scan tool.
- Use the Purge/Seal function to seal the system with a scan tool.
Important: Refer to the J 41413-200 operation manual for detailed instructions.
| ⇒ | If the difference between the FTP parameter on a scan tool and the vacuum/pressure gage on the J 41413-200 is more than 1 inch H2O replace the FTP sensor. |
| ⇒ | If the Fuel Tank Pressure Sensor parameter on a scan tool display is less than 3.2 volts, replace the FTP sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for powertrain control module (PCM) replacement, setup, and programming |
