GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Engine 🢒 Engine Controls - 2.2L (L43) 🢒 DTC P0452

Circuit Description

The powertrain control module (PCM) monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the enhanced evaporative emission (EVAP) diagnostic. The PCM supplies a 5-volt reference and ground to the sensor. The FTP sensor signal voltage increases as the FTP decreases, negative pressure or vacuum, high voltage. The FTP sensor signal voltage decreases as the FTP increases, positive pressure, low voltage. When the FTP sensor signal goes below a predetermined value, diagnostic trouble code (DTC) P0452 will set.

Conditions for Running the DTC

The key is ON.

Conditions for Setting the DTC
    • The FTP sensor voltage is less than 0.1 volt
    • All conditions present for greater than 5 seconds

Action Taken When the DTC Sets
    • The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
    • The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC
    • The malfunction indicator lamp (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.
    • A history DTC will clear after 40 consecutive warm up cycles without a fault.
    • Use a scan tool in order to clear the DTCs.

Test Description

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

  1. This step verifies that the condition is present.

    2.

  2. This step tests the 5-volt reference of the FTP sensor.

    3.

  3. This step tests if another component is causing the 5-volt reference circuit condition. If the voltage increases when a component is disconnected, replace that component.

    4.

  4. If the scan tool displays 5 volts, the FTP sensor signal circuit, the FTP sensor 5-volt reference circuit, and the PCM are OK.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Monitor the FTP sensor voltage with the scan tool.

Is the FTP sensor voltage below the specified value?

0.1 V

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Intermittent Conditions

4

  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the FTP sensor harness connector.
  3. Measure the voltage from 5-volt reference circuit of the FTP sensor with a DMM. Refer to Circuit Testing in Wiring Systems.

Does the DMM display near the specified value?

5 V

Go to Step 6

Go to Step 5

5

Disconnect the following components, while monitoring the DMM:

    • The throttle position (TP) sensor
    • The A/C pressure sensor

Does the DMM display near the specified voltage when either component is disconnected?

5 V

Go to Step 11

Go to Step 7

6

  1. Jumper the FTP sensor 5-volt reference circuit and the FTP sensor signal circuit together at the harness connector.
  2. Observe the FTP sensor voltage with a scan tool.

Does the scan tool display the specified value?

5 V

Go to Step 9

Go to Step 8

7

Test the 5-volt reference circuit of the FTP sensor for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

8

Test the signal circuit of the FTP sensor for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

9

Inspect for poor connections at the harness connector of the FTP sensor. 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 14

Go to Step 12

10

Inspect for poor connections at the harness connector of the PCM. 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 14

Go to Step 13

11

Replace the component that affected the 5-volt reference circuit. Refer to Throttle Position Sensor Replacement or Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 14

--

12

Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 14

--

13

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 14

--

14
  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 as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 15

Go to Step 2

15

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