P1456-FUEL TANK PRESSURE SENSOR CIRCUIT LOW
For a complete wiring diagram, refer to the Wiring Information.
 |
-
When Monitored:
Ignition Key on. Battery voltage greater than 10.38 volts.
-
Set Condition:
The Powertrain Control Module (PCM) detects that the Fuel Tank Pressure Sensor (FTP) input voltage is below the minimum acceptable value. One Trip Fault. Three good trips to turn off the MIL.
POSSIBLE CAUSES |
|---|
| 5-VOLT SUPPLY CIRCUIT OPEN/HIGH RESISTANCE |
| 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND |
| FTP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND |
| FTP SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT |
| FUEL TANK PRESSURE SENSOR (FTP) |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| 1. | Turn the ignition on. |
| 2. | With the scan tool, read DTCs. |
| NOTE: | Diagnose and repair any system voltage or 5-Volt Sensor Reference DTCs before continuing with this test. |
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
2. CHECK THE (K859) 5-VOLT SUPPLY CIRCUIT VOLTAGE
| 1. | Turn the ignition off. |
| 2. | Disconnect the FTP Sensor harness connector. |
| 3. | Turn the ignition on. |
| 4. | Measure the voltage on the (K859) 5-Volt Supply circuit at the FTP Sensor harness connector. |
Is the voltage between 4.8 and 5.2 volts?
Yes
- Go To 3
No
- Repair the (K859) 5-Volt Supply circuit for an open circuit or short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| 1. | With the scan tool, view the FTP Sensor voltage with the FTP Sensor harness connector disconnected. |
| NOTE: | The sensor voltage should be approximately 5.0 volts (plus or minus .1 volts) with the connector disconnected. |
Does the scan tool display the voltage as described above?
Yes
- Verify that there is good pin to terminal contact in the FTP Sensor and Powertrain Control Module connectors. Replace the FTP Sensor if no problems were found with the connectors.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Go To 4
4. CHECK THE (N7) FTP SIGNAL CIRCUIT FOR A SHORT TO GROUND
| 1. | Turn the ignition off. |
| 2. | Disconnect the PCM C1 harness connector. |
| 3. | Measure the resistance between ground and the (N7) FTP Sensor Signal circuit at the FTP Sensor harness connector. |
Is the resistance above 10k Ohms?
Yes
- Go To 5
No
- Repair the short to ground in the (N7) FTP Sensor Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
5. CHECK FOR THE (N7) FTP SENSOR SIGNAL CIRCUIT SHORTED TO THE (K917) FTP SENSOR GROUND CIRCUIT
| 1. | Measure the resistance between the (N7) FTP Sensor Signal circuit and the (K917) FTP Sensor Ground circuit at the FTP Sensor harness connector. |
Is the resistance above 10k Ohms?
Yes
- Go To 6
No
- Repair the short between the (N7) FTP Sensor Signal circuit and the (K917) FTP Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
6. POWERTRAIN CONTROL MODULE (PCM)
| 1. | Using the wiring diagram/schematic as a guide, inspect the wiring and connectors for the Powertrain Control Module (PCM). |
| 2. | Look for any chafed, pierced, pinched or partially broken wires. |
| 3. | Look for broken, bent, pushed out or corroded terminals. |
| 4. | Perform any Technical Service Bulletins that may apply. |
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Replace and program the Powertrain Control Module in accordance with the service information. (Refer to 08 - Electrical/8E - Electronic Control Modules/MODULE, Powertrain Control - Removal) .
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).