Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0452: Fuel Tank Pressure (FTP) Sensor Circuit Low VoltageDTC P0453: Fuel Tank Pressure (FTP) Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference | P0107, P0405, P0452, P0651, P2077 | P0452 | P0107, P0651, P2106, P2138 | -- |
FTP Sensor Signal | P0452 | P0452 | P0446, P0453 | -- |
Low Reference | -- | P0446 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop at idle. Parameter Normal Range: 02 V-4.8 V | |||
5-Volt Reference Voltage | 0 V | 0 V | 0.7 V |
FTP Sensor Signal | 0 V | 0 V | 5 V |
Low Reference | -- | 4.2 V | -- |
Circuit/System Description
The evaporative emission (EVAP) system is used to store fuel vapors in order to reduce the amount of fuel vapors into the atmosphere. The fuel tank pressure (FTP) sensor is only used for EVAP system diagnostics. The FTP sensor is a transducer that varies resistance according to changes in the fuel tank pressure. The engine control module (ECM) monitors the FTP sensor signal in order to detect vacuum decay and excess vacuum during the EVAP system diagnostic test. The ECM supplies a 5-volt reference and a low reference circuit to the FTP sensor.
FTP Sensor Signal Voltage | Fuel Tank Pressure |
|---|---|
High, Approximately 1.5 Volts or greater | Negative Pressure/Vacuum |
Low, Approximately 1.5 Volts or Less | Positive Pressure |
Conditions for Running the DTC
| • | The ignition is ON or the engine is operating. |
| • | The DTCs run continuously once the above condition is met. |
Conditions for Setting the DTC
P0452
The ECM detects the FTP sensor voltage is less than 0.2 volt.
P0453
The ECM detects the FTP sensor voltage is greater than 4.8 volts.
Action Taken When the DTC Sets
DTC P0452 and P0453 are Type B DTCs.
Conditions for Clearing the DTC
DTC P0452 and P0453 are Type B DTCs.
Diagnostic Aids
| • | If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected. |
| • | The scan tool 5 volt reference parameter should display between 4.8-5.2 volts. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the DTC information with a scan tool. DTC P0651 should not set.
- Observe the scan tool FTP Sensor voltage parameter. The reading should be between 0.2-4.0 volts.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
| ⇒ | If DTC P0651 is set, refer to DTC P0641 or P0651. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the FTP sensor.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
- Verify the scan tool FTP Sensor voltage parameter is less than 4.8 volts
- Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify the scan tool FTP Sensor voltage parameter is greater than 4.8 volts.
- If all circuits test normal, test or replace the FTP sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
