DTC P0452. Saturn L300/LW300 2003

For 1990-2009 cars only

Makes 🢒 Saturn 🢒 2003 🢒 L300/LW300 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 DTC P0452

Engine Controls Component Views
Engine Controls Schematics

Circuit Description

The control module monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the evaporative emission (EVAP) diagnostic test. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. If the control module detects the FTP sensor signal voltage below a calibrated value, this DTC will set.

The following table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.

FTP Sensor Signal Voltage	Fuel Tank Pressure
High, Approximately 2.5 Volts or More	Positive Pressure
Low, Approximately 2.5 Volts or Less	Negative Pressure/Vacuum

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The FTP sensor voltage is less than 0.2 volts, for more than 3 seconds.

Action Taken When the DTC Sets

•	The control module illuminates the malfunction indicator lamp (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 DTC

•	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 non-emission related diagnostic.

•	Clear the DTC with a scan tool.

Diagnostic Aids

•	The FTP sensor parameter on the scan tool should read between 2.35 and 2.85 volts with the ignition ON, engine OFF and the fuel cap removed. This represents atmospheric pressure of 0 inches H2O of vacuum.

•	The FTP sensor 5-volt reference circuit is shared with the following sensors:

-	The camshaft position (CMP) sensor

-	The exhaust gas recirculation (EGR) sensor

-	The mass air flow (MAF) sensor

-	The manifold absolute pressure (MAP) sensor

-	The air conditioning (A/C) pressure sensor

-	The accelerator pedal position (APP) sensor 1

•	The FTP sensor low reference circuit is shared with the following sensors:

-	The A/C pressure sensor

-	The fuel level sensors

-	The APP sensor 2

•	Inaccurate readings will occur if resistance measurements are taken on a FTP sensor. The FTP sensor contains an internal amplifier circuit that requires applied voltage to function properly

•	To locate an intermittent problem, monitor the FTP sensor voltage with the ignition ON, engine OFF. Wiggling wires, while watching for change in the FTP sensor voltage, may help locate the area where fault may exist.

•	For intermittent conditions, refer to Intermittent Conditions

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

Observe the fuel tank press. sensor parameter with a scan tool.

Is the parameter less than the specified value?

0.1 V

Go to Step 4

Go to Step 3

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text. Attempt to duplicate the Freeze Frame/Failure Records that you observed.

Does the DTC fail this ignition?

Go to Step 4

Go to Diagnostic Aids

Turn OFF the ignition.
Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Disconnect the fuel tank wiring harness connector at the rear of the fuel tank.
Turn ON the ignition, with the engine OFF.
Observe the fuel tank press. sensor parameter with a scan tool.

Is the parameter less than the specified value?

4.8 V

Go to Step 8

Go to Step 5

Turn ON the ignition, with the engine OFF.
At the fuel tank wiring harness connector, measure the voltage from the 5-volt reference circuit of the fuel tank pressure (FTP) sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage within the specified value?

4.8-5.2 V

Go to Step 9

Go to Step 6

Disconnect the following components, while monitoring the DMM:

•	The manifold absolute pressure (MAP) sensor

•	The camshaft position (CMP) sensor

•	The exhaust gas recirculation (EGR) valve

•	The mass air flow (MAF) sensor

•	The accelerator pedal position (APP) sensor 1

•	The air conditioning (A/C) pressure sensor

Is the DMM within the specified value when any of the components are disconnected?

4.8-5.2 V

Go to Step 12

Go to Step 7

Test the FTP 5-volt reference circuit for an open or for a short to ground between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.