Circuit Description
The Fuel Tank Pressure sensor responds to changes in the fuel tank pressure or vacuum. This information is used in order to detect vacuum decay or an excessive vacuum during the EVAP diagnostic routing. The fuel tank pressure sensor signal voltage to the VCM varies from a minimum of about 0.1 volts with pressure in the fuel tank to above 4.0 volts with a high vacuum in the fuel tank.
The Fuel Tank Pressure sensor display on the scan tool has an auto zero feature which occurs at each ignition cycle and is corrected according to the barometric pressure. Because of this, the Fuel Tank Pressure sensor display may not accurately reflect the actual output of the sensor or the conditions within the fuel tank.
The Fuel Tank Pressure sensor diagnosis table is intended to isolate and diagnose the electrical problems with the sensor wiring or the sensor.
Conditions for Running the DTC
The ignition switch is in the RUN position.
Conditions for Setting the DTC
The Fuel Tank Pressure sensor voltage is less than 0.1 volt for more than 5 seconds.
Action Taken When the DTC Sets
The VCM turns ON the MIL after 2 consecutive driving cycles with the fault active.
Conditions for Clearing the MIL or DTC
| • | The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed. |
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle. |
| • | Use a scan tool in order to clear the DTCs. |
Diagnostic Aids
- Inspect the Control Module harness connectors for the following conditions:
- Inspect the wiring harness for damage. If the harness appears to be OK, observe the Fuel Tank Pressure sensor display on the scan tool while moving the connectors and the wiring harnesses related to the sensor. A change in the display will indicate the location of the fault. Refer to Wiring Repairs in Electrical Diagnosis if a fault in the wiring is found.
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed |
| • | Damaged terminals |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and the Failure Records for reference. This information will be lost when the Clear DTC Information function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||||
2 |
Does the scan tool display indicate the Fuel Tank Pressure Sensor within the specified value? | -1.0 - 1.0 in H2O | ||||||||||
3 | This DTC is intermittent. Are any additional DTCs stored? | -- | Go to the applicable DTC table | Go to Diagnostic Aids | ||||||||
4 |
Is the voltage near the specified value? | 5.0 V | ||||||||||
Is the voltage between the specified values? | 1.3 v - 2.0 V | |||||||||||
6 | Check for an open in the 5 V reference circuit. Was a problem found? | -- | ||||||||||
7 | Check for a short to ground in the 5 V Reference circuit. Was a problem found? | -- | ||||||||||
8 | Check the 5 V reference circuit for a poor terminal connection at the VCM. Was a problem found? | -- | ||||||||||
9 | Check for an open in the sensor ground circuit. Was a problem found? | -- | ||||||||||
10 | Check the sensor ground circuit for a poor terminal connection at the VCM. Was a problem found? | -- | ||||||||||
11 | Check the Fuel Tank Pressure Sensor signal for a short to ground. Was a problem found? | -- | ||||||||||
12 | Check the Fuel Tank Pressure Sensor signal terminal connection at the VCM. Was a problem found? | -- | ||||||||||
13 | Check the connector at the Fuel Tank Pressure Sensor for:
Was a problem found? | -- | ||||||||||
14 | Replace the Fuel Tank Pressure Sensor. Refer to Fuel Tank Pressure Sensor Replacement in Repair Instructions. Is the action complete? | -- | -- | |||||||||
15 | Repair the circuit as necessary. Refer to Wiring Repairs in Repair Instructions. Is the action complete? | -- | -- | |||||||||
16 |
Is the action complete? | -- | -- | |||||||||
17 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||||||||||
18 | Use the scan tool in order to display the Capture Info and the Review Capture Info functions. Are there any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
