DTC P0452 or P0453 (LAU or LBW)
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DTC P0452 or P0453 (LAU or LBW)
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DTC P0452
Fuel Tank Pressure Sensor Circuit Low Voltage
DTC P0453
Fuel Tank Pressure Sensor Circuit High Voltage
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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5 V Reference
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P0122, P0452, P0642
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P0452, P0641
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P0453, P0643
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P0641, P0642, P0643
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FTP Sensor Signal
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P0452
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P0452
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P0453
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-
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Low Reference
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-
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P0446
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-
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-
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FTP Sensor
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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:
Engine idling with closed loop control
Parameter Normal Range:
0.2-4.8 V
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5 V Reference
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0 V
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0 V
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5 V
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FTP Sensor Signal
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0 V
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0 V
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5 V
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Low Reference
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-
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4.2 V
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-
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Circuit/System Description
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The evaporative emission (EVAP) system is used to store fuel vapors in order to reduce the amount of fuel vapors into the atmosphere. The fuel tank pressure (FTP) sensor is only used for EVAP system diagnostics. The FTP sensor is a transducer that varies resistance according to changes in the fuel tank pressure. The engine control module (ECM) monitors the FTP sensor signal in order to detect vacuum decay and excess vacuum during the EVAP system diagnostic test. The ECM supplies a 5 V reference and a low reference circuit to the FTP sensor.
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FTP Sensor Signal Voltage
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Fuel Tank Pressure
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High, Approximately 1.5 V or More
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Negative Pressure/Vacuum
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Low, Approximately 1.5 V or Less
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Positive Pressure
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Conditions for Running the DTC
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The engine speed is greater that 240 RPM.
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The DTCs run continuously when the above condition is met for 105 Vs.
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Conditions for Setting the DTC
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P0452
The ECM detects the FTP sensor signal voltage is less than 0.2 V for 4 s, or a cumulative of 30 s.
P0453
The ECM detects the FTP sensor signal voltage is greater than 4.85 V for 4 s, or a cumulative of 30 s.
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Action Taken When the DTC Sets
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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 P0452 and P0453 are Type B DTCs.
If a shared 5 V reference circuit is shorted to ground or shorted to a voltage, other 5 V reference circuits may be affected.
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTCs P0641, P0642 or P0643 should not set.
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3.
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Observe the FTP Sensor voltage parameter. The FTP sensor voltage should be between 0.2-4.8 V.
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4.
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Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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1.
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Ignition OFF, remove the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
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2.
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Disconnect the multi-way harness connector X10, located near the fuel tank.
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3.
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Test for less than 5 Ω between the low reference circuit terminal F and ground.
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4.
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If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
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5.
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Install the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
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6.
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Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal D and ground.
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7.
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If less than the specified range, test the 5 V reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
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8.
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If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
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9.
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Observe the scan tool B150 FTP sensor parameter. Verify that the FTP Sensor parameter is less than 4.8 V.
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10.
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If greater than the specified value, test the signal circuit terminal E for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
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11.
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Install a 3 A fused jumper wire between the signal circuit terminal E and the 5 V reference circuit terminal D. Verify that the scan tool FTP Sensor parameter is greater than 4.8 V.
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12.
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If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
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14.
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Disconnect the B150 FTP sensor connector.
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15.
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Inspect the FTP sensor circuits in the fuel tank harness, between the FTP sensor connector and X10 for the following conditions, and repair as necessary:
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Damaged wiring or terminals
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16.
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If all circuits/connections test normal, test or replace the B150 FTP sensor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
