P0455
DTC P0455SYSTEM DESCRIPTION
The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.
The table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.
CONDITIONS FOR RUNNING THE DTC
- DTC P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0156, P0157, P0158, P0159, P0160, P0161, P0221, P0222, P0223, P0443, P0446, P0449, P0451, P0452, P0453, P0455, P0458, P0459, P0498, P0499, P0506, P0507, P1271, P1277, P1278, P1282, P1283, P1511, P1516, P1519, P1523, P1526, P1530, P1551, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, P2138, P2176 are not set.
- The engine is running.
- The ignition voltage is between 10.5-17.3 volts.
- The barometric pressure (BARO) is more than 68 kPa.
- The fuel level is between 15-85 percent.
- The intake air temperature (IAT) is between 4-35°C (39-95°F).
- The start-up ECT and IAT are within 9°C (16°F) of each other.
- The vehicle speed is 0 kph (0 mph).
CONDITIONS FOR SETTING THE DTC
The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
- If DTC P0442, P0446, P0455 is set, EVAP special functions on the scan tool will not be allowed. Clear DTCs before performing these tests.
- The ECM uses the FTP sensor to detect the pressure of fuel vapor in the fuel tank during all parts of the EVAP diagnostic system test. Ensure the FTP sensor is not skewed by verifying FTP sensor on the scan tool is between 2.35-2.85 volts with the ignition ON and the engine OFF.
- The following are possible causes of a large EVAP leak:
- The fuel cap is missing, incorrectly installed or leaking.
- The EVAP canister vent solenoid valve is stuck open.
- The EVAP canister purge solenoid valve is stuck closed/blocked or a lack of manifold vacuum to solenoid.
- The EVAP line/hose connections are disconnected/leaking.
- The fuel sender O-ring is leaking.
- The FTP sensor seal is leaking.
- To help locate intermittent leaks, use the J 41750 OBD II/Enhanced Emissions Testing Equipment (Cart Only) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
- To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT.
- Review the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.
- For intermittent conditions, refer to Intermittent Conditions. Intermittent Conditions
TEST
Steps 1-3:
Steps 4-7:
Steps 8-16:
