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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2006 🢒 Chevy K Silverado - 4WD (CNG) 🢒 Engine 🢒 Engine Controls - 6.0L 🢒 DTC P1433

Circuit Description

The compressed natural gas (CNG) fuel tank pressure (FTP) sensor is a pressure transducer. The fuel injector control module (FICM) supplies about 5 volts on the FTP sensor reference voltage circuit. The FICM also supplies a signal circuit and a low reference circuit to the FTP sensor. When fuel level/tank pressure is full the FTP signal voltage rises to 4.1 volts. As fuel level/tank pressure decreases to empty, the FTP signal voltage drops to around 0.5 volts. The FICM communicates the FTP data to the powertrain control module (PCM) by a pulse width modulated (PWM) circuit. The PCM uses the FTP sensor and the fuel tank temperature (FTT) sensor in order to determine the amount of fuel within the fuel tank.

This DTC sets when the FTP sensor signal voltage is greater than the normal operating range of the sensor.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1433 Fuel Pressure Sensor Circuit High Voltage

Conditions for Running the DTC
    • The ignition voltage is more than 4 volts.
    • DTCs P0182, P0183, or P1207 are not set.
    • The FTT is less than 30°C (86°F).

Conditions for Setting the DTC
    • The FTP signal voltage is more than 4.95 volts.
    • The condition exists for at least 2 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module switches over to gasoline fuel operation.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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.

Test Description

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

  1. This step determines if the condition is present.

    2.

  2. This step determines if an open sensor ground circuit condition is present. The FTP and FTT share a sensor ground. An open circuit between the splice and the ground terminal will cause both signal circuits to indicate high voltage.

    3.

  3. This step determines if an open or shorted signal circuit is the cause of the condition.

    4.

  4. This step determines if a shorted 5-volt reference circuit is the cause of the condition.

    5.

  5. This step determines if an open sensor ground circuit between the harness connector of the FTP sensor and the splice is the cause of the condition.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the Fuel Tank Pressure (FTP) data parameter with a scan tool.

Does the scan tool display the FTP sensor voltage more than the specified value?

4.95 V

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame and/or the Failure Records data for this DTC.
  2. Turn the ignition OFF 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 and/or the Failure Records data.

Does the DTC fail this ignition cycle?

--

Go to Step 4

Go to Intermittent Conditions

4

Observe the fuel tank temperature (FTT) sensor data parameter with a scan tool.

Does the scan tool display the FTT sensor voltage more than the specified value?

4.5 V

Go to Step 12

Go to Step 5

5

  1. Remove the fuel tank cover. Refer to Fuel Tank Cover Replacement .
  2. Disconnect the harness connector of the FTP sensor.
  3. Connect a 3-amp fused jumper wire between the signal circuit of the FTP sensor and a known good ground.

    4. Important: If the jumper fuse opens, repair the signal circuit short to battery voltage.

  4. Observe the FTP sensor data parameter with a scan tool.

Does the scan tool display the FTP sensor voltage less than the specified value?

0.25 V

Go to Step 6

Go to Step 8

6

  1. Remove the jumper.
  2. Measure the voltage from the 5-volt reference circuit of the FTP sensor with a DMM.

Does the DMM display a voltage more than the specified value?

5.2 V

Go to Step 9

Go to Step 7

7

Probe the ground circuit of the FTP sensor with a test lamp connected to B+.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 13

8

Test the signal circuit of the FTP sensor for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 11

9

Test the 5-volt reference circuit of the FTP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

10

Inspect for proper terminal contact at the harness connector of the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

11

Inspect for proper terminal contact at the harness connector of the fuel injector control module (FICM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

12

Repair the ground circuit of the FTP sensor for an open between the ground terminal and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you complete the repair?

--

Go to Step 16

--

13

Repair the ground circuit of the FTP sensor for an open, or high resistance, between the harness connector of the FTP sensor and the splice. Refer to Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you complete the repair?

--

Go to Step 16

--

14

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

Did you complete the replacement?

--

Go to Step 16

--

15

Replace the FICM. Refer to Fuel Injector Control Module Replacement .

Did you complete the replacement?

--

Go to Step 16

--

16
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30  seconds.
  3. Turn ON the ignition, with the engine OFF.
  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 17

17

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK