Engine Controls - Revised DTC P0452 and P0453 Diagnosis
Bulletin No.: 04-06-04-018Date: March 24, 2004
SERVICE MANUAL UPDATE
Subject:
Service Manual Update - Diagnostic Trouble Code (DTC) P0452 and P0453
Models:
2004 Saturn VUE Vehicles
with 3.5L V-6 Engine (VIN 4 - RPO L66)
Attention:
Fixed Operations Manager and Technician
Purpose
The purpose of this bulletin is to inform Saturn retailers of revised diagnostic procedures for DTC P0452 (fuel tank pressure sensor [FTPS] below calibrated value) and DTC P0453 (FTPS above calibrated value) for 2004 model year Saturn VUE vehicles.
The diagnostic procedures are being revised to reflect the correct voltage values associated with each DTC. The previous printed versions of the 2004 Saturn VUE Service Manual, Vol. 1 had voltage values that were reversed between the two DTCs.
Please obtain all copies of the 2004 Saturn VUE Service Manual, Vol. 1 at your facility. Make copies of the following diagnostic information and insert pages 6-1211 through 6-1216 into your 2004 Saturn VUE Service Manual, Vol. 1 for corrected diagnostic procedures and repair process.
Important:
This Service Manual update applies to only 2004 model year Saturn VUE 3.5L V-6 (RPO L66) equipped vehicles. The 2005 model year Service Manual information for DTC P0452 and P0453 is correct.
The SI website will be updated immediately and future Service Stall System SI CD releases will include this and other Service Manual update.
Circuit Description
The DTC P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage diagnostic monitors the function of the FTP sensor circuit. The control module monitors the 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 above a calibrated value, DTC P0452 will set.
The table shown illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.
DTC Descriptor
This diagnostic supports the following DTC.
DTC P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage.
Conditions for Running the DTC
^ DTC P0453 is not set.
^ The ignition is ON.
^ DTC P0452 runs once per drive cycle when the above conditions are met.
Conditions for Setting the DTC
The FTP sensor voltage is more than 4.9 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 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
^ The FTP sensor parameter on the scan tool should read between 1.4 volts and 1.5 volts with the ignition ON, engine OFF and the fuel cap removed. This represents atmospheric pressure of O inches H20 of vacuum.
^ The FTP sensor 5-volt reference circuit is shared with the following sensors:
- Exhaust Gas Recirculation (EGR) sensor
- A/C Refrigerant Pressure Sensor
- A/T Input Shaft Speed (ISS) Sensor
- Accelerator Pedal Position (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 the Intermittent Conditions diagnostic table in the Engine Controls section of the 2004 Saturn VUE Service Manual, Vol.1.
Test Description
The number below refers to the step number on the diagnostic tables shown.
2. If DTC P0651 set, the 5-volt reference circuit may be shorted to a voltage.
12. After replacing the PCM, a new minimum throttle position and idle speed must also be established.
Circuit Description
The DTC P0453 Fuel Tank Pressure (FTP) Sensor Circuit High Voltage diagnostic monitors the function of the FTP sensor circuit. The control module monitors the 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, DTC P0453 will set.
The table shown illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.
DTC Descriptor
This diagnostic supports the following DTC.
DTC P0453 Fuel Tank Pressure (FTP) Sensor Circuit High Voltage.
Conditions for Running the DTC
^ DTC P0452 is not set.
^ The ignition is ON.
^ DTC P0453 runs once per drive cycle when the above conditions are met.
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 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
^ The FTP sensor parameter on the scan tool should read between 1.4 volts and 1.5 volts with the ignition ON, engine OFF and the fuel cap removed. This represents atmospheric pressure of O inches H20 of vacuum.
^ The FTP sensor 5-volt reference circuit is shared with the following sensors:
- Exhaust Gas Recirculation (EGR) sensor
- A/C Refrigerant Pressure Sensor
- A/T Input Shaft Speed (ISS) Sensor
- Accelerator Pedal Position (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 the Intermittent Conditions diagnostic table in the Engine Controls section of the 2004 Saturn VUE Service Manual, Vol.1.
Test Description
The number below refers to the step number on the diagnostic table shown.
2. If DTC P0651 set, the 5-volt reference circuit may be shorted to ground.
5. This step tests for the proper operation of the circuit in the high voltage range.
11. After replacing the PCM, a new minimum throttle position and idle speed must also be established.
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