• | 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. |
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 | -- | -- |
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 | -- |
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 More | Negative Pressure/Vacuum |
Low, Approximately 1.5 Volts or Less | Positive Pressure |
• | The ignition is ON or the engine is operating. |
• | The DTCs run continuously once the above condition is met. |
The ECM detects the FTP sensor voltage is less than 0.2 volt.
The ECM detects the FTP sensor voltage is more than 4.8 volts.
DTC P0452 and P0453 are Type B DTCs.
DTC P0452 and P0453 are Type B DTCs.
• | 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. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If DTC P0651 is set, refer to DTC P0641 or P0651 . |
⇒ | If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit/connections test 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/connections test normal, replace the ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than the specified value, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module replacement, setup, and programming |