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Home >> Cadillac >> 2005 >> CTS Base, 2.8 T, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 2.8L (DTC P0420 To P1551) >> Engine Controls Diagnosis >> DTC P0452 >> Test Description

Test Description

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

  1. 4:  The ECM produces a measurable steady state amperage that provides the 5-volt reference to the FTP sensor. If the amperage on the 5-volt reference circuit is less than 80 mA, test the 5-volt reference circuit for an open or high resistance.
  2. 5:  This step tests the signal circuit of the FTP sensor.
P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Control Module (ECM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the fuel tank pressure (FTP) sensor voltage parameter with a scan tool.
Is the voltage less than the specified value?		 0.13 V Go to Step 4  Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn ON the ignition, with the engine OFF.
  2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Disconnect the FTP sensor connector at the evaporative emission (EVAP) canister.
  4. Set-up a DMM to test amperage on the 400 mA scale.
  5. Measure the amperage from the 5-volt reference circuit of the FTP sensor to a good ground.
Is the amperage more than the specified value?		 80 mA Go to Step 5  Go to Step 7 
5 
  1. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the FTP sensor and the signal circuit of the FTP sensor.
  2. Observe the FTP Sensor voltage parameter, with a scan tool.
Is the voltage more than the specified value?		 4.8 V Go to Step 8  Go to Step 6 
6 Test the signal circuit of the FTP sensor for an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
7
IMPORTANT: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnosis the applicable circuits and components.
Test the 5-volt reference circuit of the FTP sensor for an open, or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
8 Test for an intermittent and for a poor connection at the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections andConnector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 10 
9 Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
10 Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 12  -
11 Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 12  -
12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 13 
13 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information System OK
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