P0452
DTC P0452
DTC DESCRIPTORS
DTC P0452
Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage
DIAGNOSTIC FAULT INFORMATION
IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection
TYPICAL SCAN TOOL DATA
FTP Sensor Voltage:
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. Before using this signal as an atmospheric reference it must first be re-zeroed.
CONDITIONS FOR RUNNING THE DTC
DTC P0452 runs continuously when the ignition is ON.
CONDITIONS FOR SETTING THE DTC
The FTP sensor voltage is less than 0.1 volt for more than 5 seconds.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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.
CIRCUIT/SYSTEM VERIFICATION
1. Remove the fuel cap.
2. Turn ON the ignition, with the engine OFF.
3. Observe the Fuel Tank Pressure Sensor parameter with a scan tool.
4. The FTP Sensor parameter should be 1.5 volts
CIRCUIT/SYSTEM TESTING
1. If DTC P0641 is set, repair that DTC first.
2. With the ignition OFF, disconnect the harness connector at the FTP sensor.
3. With the ignition ON, measure for 4.8-5.2 volts between the 5-Volt reference circuit of the FTP sensor and ground.
- If over 5.2 volts, inspect for unexpected voltage at the circuit or faulty control module.
- If under 4.8 volts, inspect for a short to ground, open/high resistance at the circuit or faulty control module.
4. With the ignition ON, measure for less than 5 ohms of resistance between the low reference circuit of the FTP sensor and a good ground.
- If greater than 5 ohms, inspect for an open/high resistance in the circuit or faulty control module.
5. With the ignition ON, the scan tool FTP sensor parameter should indicate 4.8-5.2 volts with a 3-amp fused jumper wire connecting the FTP signal circuit to the 5-Volt reference circuit.
- If under 4.8 volts, test for a short to ground or an open at the circuit or a faulty control module.
- If the circuits and control module test OK, replace the FTP sensor.
REPAIR INSTRUCTIONS
IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Fuel Tank Pressure Sensor Replacement
- Control Module References for ECM replacement, setup, and programming Verification Tests