Circuit Description
The fuel tank pressure sensor measures the pressure (or vacuum) in the fuel tank. The PCM provides the sensor with a reference voltage, a signal circuit, and a ground. The sensor returns a signal voltage to the PCM relative to the pressure in the fuel tank. The PCM should see a signal voltage increase as the pressure in the tank decreases (more vacuum). As the pressure in the tank increases (less vacuum), the PCM should see a signal voltage decrease. The PCM uses the sensor signal to test the integrity of the EVAP system. If the PCM detects a signal voltage that is too high, DTC P0453 will set.
Conditions for Running the DTC
The ignition is on.
Conditions for Setting the DTC
The fuel tank pressure sensor voltage is more than 4.9 volts for at least 1 second.
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 has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data. |
| • | The PCM will disable the EVAP system. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC Information function. |
Diagnostic Aids
If the condition is intermittent, refer to Intermittent Conditions in Symptoms.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if the malfunction is present. If DTC P1639 sets at the same time, this indicates that the 5.0 volt reference circuit is either shorted to ground or shorted to a voltage.
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Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.
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This step tests whether the signal circuit is shorted to a voltage.
-
This step tests whether a ground circuit is available for the Fuel Tank Pressure sensor at the connector C415.
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This step tests whether a ground circuit is available for the Fuel Tank Pressure sensor.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Is DTC P1639 also set? | -- | |||
3 |
Is the Fuel Tank Pressure sensor voltage above the specified value? | 4.7V | ||
Does the scan tool indicate that this diagnostic failed this ignition? | -- | Go to Diagnostic Aids | ||
Is the Fuel Tank Pressure sensor voltage below the specified value? | 1.0V | |||
Probe the sensor ground circuit at connector C415 (PCM side) with a test lamp connected to B+. Is the test lamp illuminated? | -- | |||
7 | Measure the voltage at the 5.0 volt reference circuit at the connector C415 to battery ground with the DMM. Is the voltage near the specified value? | 5.0V | ||
8 | Inspect for a poor connections at connector C415. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
9 |
Is the Fuel Tank Pressure sensor voltage below the specified value? | 1.0V | ||
Probe the Fuel Tank Pressure sensor ground circuit with a test lamp connected to B+ at the Fuel Tank Pressure sensor jumper harness (PCM side). Is the test lamp illuminated? | -- | |||
11 | Measure the voltage at the Fuel Tank Pressure sensor 5.0 volt reference circuit to the battery ground with the DMM. Refer to Measuring Voltage in Wiring Systems. Is the voltage near the specified value? | 5.0V | ||
12 | Test the Fuel Tank Pressure sensor signal circuit for a short to voltage or a short to the 5 volt reference circuit between connector C415 and the PCM. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
13 |
Did you find and correct the condition? | - | ||
14 | Inspect for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | - | ||
15 | Repair the 5 volt reference circuit for a short to voltage between the PCM and the connector C415. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
16 | Repair the signal circuit for a short to voltage in the Fuel Tank Pressure sensor jumper harness. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
17 | Repair the open ground circuit in the Fuel Tank Pressure sensor jumper harness. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
18 | Repair the 5 volt reference circuit in the Fuel Tank Pressure jumper harness for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
19 | Inspect for a poor connections at the Fuel Tank Pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections in and Connector Repairs Wiring Systems. Did you find and correct the condition? | -- | ||
20 | Replace the Fuel Tank Pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement . Is the action complete? | -- | -- | |
21 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | |
22 |
Does the scan tool indicate that this test ran and passed? | -- | ||
23 | Select the Capture Info option and the Review Info option with the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
