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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1383 (Engine Control System Diagnosis (DTC P0130 To DTC P0456) -- 1.8L (LNK)) >> Diagnosis >> DTC P0452 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 1:  The Diagnostic System Check- Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
  2. 2:  This step determines if a FTP sensor malfunction is present. The input signal of the FTP sensor should indicate atmospheric pressure with the fuel tank filler cap removed. The fuel tank pressure sensor will vary with atmospheric pressure. A typical pressure at sea level is between 0.0-0.99 mm Hg (0.0-0.5 in H2O).
  3. 5:  This step checks for an open in the FTP sensor reference voltage circuit.
  4. 6:  The FTP sensor signal circuit carries a 5 volt bias that can be measured with the DMM. If the measured voltage is near zero there is a short to ground or a faulty PCM.
  5. 12:  The EVAP system diagnostic can be monitored on the scan tool under the I/M System Information selection. When the EVAP test displays a YES status, indicating that the system diagnostic is completed, check for DTC P0452 in the Last Test Failed screen of the scan tool. If there is no DTC P0452 displayed the EVAP system diagnostic has run and passed, indicating that no malfunction was present this time. DTCs MUST be cleared in order to view the Current Status of the system diagnostics being performed. Do not forget that the I/M System Information tests only indicate that the test has run, not if the test passed or failed. The Last Test Failed screen must be checked for related DTCs in order to determine the outcome of the diagnostic test involved. This step checks for an open in the FTP sensor ground circuit.
DTC P0452

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Powertrain Control Module (PCM) Connector End Views  or  Engine Controls Connector End Views 
1  Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 
  1. Loosen the fuel tank filler cap in order to release any pressure inside the fuel tank.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the fuel tank pressure (FTP) sensor parameter on the scan tool.
Is the FTP sensor within the specified range?		 0.0-0.99 mm Hg (0.0-0.5 in H2O) Go to Step 3  Go to Step 4 
3
  1. Use the scan tool in order to clear the DTCs.
  2. Start the engine.
  3. Operate the vehicle within the Freeze Frame conditions as specified or within the Conditions for Running the DTC. Review the supporting text.
Did DTC P0452 set?		 - Go to Step 4  Go to Diagnostic Aids
4 Was DTC P0122 also set? - Go to Step 9  Go to Step 5 
5 
  1. Turn OFF the ignition.
  2. Disconnect the FTP sensor electrical connector. Refer to Fuel Tank Pressure Sensor Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the 5-volt reference circuit of the FTP sensor with a DMM.
Is the voltage near the specified value?		 5.0 V Go to Step 6  Go to Step 8 
6  Measure the voltage of the FTP sensor input circuit with a DMM.
Is the voltage near the specified value?		 4.9 V Go to Step 10  Go to Step 7 
7
  1. Test the FTP sensor input circuit for a short to ground.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Was a repair necessary?		 - Go to Step 12  Go to Step 11 
8 Repair the open in the 5-volt reference sensor circuit between the FTP sensor and SP108. Refer to Wiring Repairs in Wiring Systems.
Is the action complete?		 - Go to Step 12  -
9 Repair the open in the 5-volt reference sensor circuit between the PCM and SP108. Refer to Wiring Repairs in Wiring Systems.
Is the action complete?		 - Go to Step 12  -
10 Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Is the action complete?		 - Go to Step 12  -
11 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Is the action complete?		 - Go to Step 12  -
12 
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC or until the EVAP test is complete. Review the Test Description.
Does the DTC run and pass?		 - Go to Step 13  Go to Step 2 
13 With a scan tool, observe the stored information, Capture Info.
Does the scan tool display any DTCs that you have not diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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