DTC P0451-P0454 (LF1, LFW)
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DTC P0451-P0454 (LF1, LFW)
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DTC P0451
Fuel Tank Pressure Sensor Performance
DTC P0452
Fuel Tank Pressure Sensor Circuit Low Voltage
DTC P0453
Fuel Tank Pressure Sensor Circuit High Voltage
DTC P0454
Fuel Tank Pressure Sensor Intermittent
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Diagnostic Fault Information
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Circuit
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Short to Ground
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High Resistance
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Open
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Short to Voltage
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Signal Performance
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Fuel Tank Pressure Sensor 5V Reference
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P0452, P0532, P0641
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P0451
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P0446, P0452
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P0453, P0641
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-
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Fuel Tank Pressure Sensor Signal
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P0452
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P0451
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P0452
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P0453
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P0451, P0454
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Fuel Tank Pressure Sensor Low Reference
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-
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P0446, P0451
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P0446
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-
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P0451
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Fuel Tank Pressure Sensor Voltage
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Circuit
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Short to Ground
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Open
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Short to Voltage
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Operating conditions:
Ignition ON, Engine OFF
Parameter Normal Range:
1.3-1.7 V
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Fuel Tank Pressure Sensor 5V Reference
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0 V
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0 V
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4.2-5 V
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Fuel Tank Pressure Sensor Signal
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0 V
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0 V
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5 V
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Fuel Tank Pressure Sensor Low Reference
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-
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4.5 V
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-
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Circuit/System Description
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The fuel tank's pressure sensor measures the air pressure or vacuum in the EVAP system. The engine control module (ECM) supplies the sensor with a 5 V reference and a low reference circuit for the fuel tank's pressure sensor. The fuel tank pressure sensor signal voltage varies depending on EVAP system pressure or vacuum. The controller also uses this fuel tank pressure 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.
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Conditions for Running the DTC
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P0451
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DTC P0451 runs only when the engine-off natural vacuum small leak test, P0442, executes.
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The number of times this test runs can range from 0-2 per engine-off period. The length of the test can be up to 10 minutes.
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P0452 and P0453
DTC P0452 and P0453 run continuously when the ignition is ON.
P0454
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DTC P0454 runs only when the engine-off natural vacuum small leak test, P0442, executes.
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This test can run once per engine-off period. The length of the test can be up to 10 minutes.
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A refueling event is not detected.
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Conditions for Setting the DTC
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P0451
This DTC will set if the controller is unable to re-zero the fuel tank pressure sensor voltage within a calibrated range during the engine-off small leak test, P0442.
P0452
The fuel tank pressure sensor voltage is less than 0.1V for more than 5 seconds.
P0453
The fuel tank pressure sensor voltage is more than 4.9V for more than 5 seconds.
P0454
If, during the engine-off natural vacuum small leak test, P0442, the ECM detects an abrupt fuel tank pressure signal change, other than a refueling event, this DTC will set. An abrupt change is defined as a change of 0.45 inch H2O in the span of 1 second.
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Action Taken When the DTC Sets
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DTCs P0451 and P0454 are Type A DTCs.
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DTCs P0452 and P0453 are Type B DTCs.
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Conditions for Clearing the MIL/DTC
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DTCs P0451 and P0454 are Type A DTCs
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•
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DTCs P0452 and P0453 are Type B DTCs
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P0451 and P0454
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A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
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Ensure that the reference port on the fuel tank pressure sensor is unobstructed.
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An fuel tank pressure sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the
J 41413-200
EEST while taking a snapshot.
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Schematic Reference
Engine Controls Schematics (3.0L (LF1))
Engine Controls Schematics (2.8L (LAU))
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
Special Tools
J 41413-200
Evaporative Emission System Tester (EEST)
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Circuit/System Verification
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2.
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Ignition ON, engine OFF.
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3.
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Observe the Fuel Tank Pressure Sensor parameter with a scan tool.
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4.
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The Fuel Tank Pressure Sensor parameter should be 1.3-1.7 V.
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1.
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Ignition OFF, disconnect the harness connector at the B150 fuel tank pressure sensor.
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2.
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Ignition OFF, test for less than 5 Ω of resistance between the low reference circuit terminal 2 and ground.
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3.
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If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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4.
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Ignition ON, test for 4.8-5.2V between the 5V reference circuit terminal 3 and ground.
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5.
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If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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6.
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If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
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7.
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Verify the scan tool B150 fuel tank pressure sensor parameter is less than 0.2V.
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8.
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If greater than the specified range, test the signal circuit's pin 1 for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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9.
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Install a 3A fused jumper wire between the signal circuit terminal 1 and the 5V reference circuit terminal 3. Verify the scan tool fuel tank pressure sensor parameter is greater than 4.7V.
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10.
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If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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11.
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If all circuits test normal, test or replace the B150 fuel tank pressure sensor.
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For DTC P0451 or P0454, clear DTCs with a scan tool.
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