2010 Cadillac CTS Sedan AWD V6-3.6L Page 1458
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0455
- Evaporative Emission (EVAP) System Large Leak Detected
DTC P0497
- Evaporative Emission (EVAP) System No Flow During Purge
Circuit/System Description
The control module tests the evaporative emission (EVAP) system for a large leak, or a stuck closed EVAP canister purge valve. 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 valve OPEN and the EVAP vent 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 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 increases too slowly, a DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and
vent valves.
Conditions for Running the DTC
* Before the engine control module (ECM) can report DTC P0455 or DTC P0497 failed, DTCs P0446 and P0496 must run and pass.
* DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0443, P0446, P0449, P0450, P0451, P0452,
P0453, P0458, P0459, P0496, P0498, P0499, P0560, P0562, P0563, P0700, P2122, P2123, P2127, P2128, P2138, P2227, P2228, or P2229 is
not set.
* The ignition voltage is between 10-18 V.
* The engine run time is greater than 10 min or the fuel trim is stable.
* The fuel tank pressure (FTP) is between -18.7 and +9.8 mm Hg (-10.0 and +5.2 in. H2O).
* The Closed Loop fuel control is enabled.
* The engine is idling.
* The barometric pressure (BARO) is greater than 68 kPa.
* The fuel level is between 11-88 %.
* The ambient air temperature (IAT) is between 2-32掳C (36-90掳F).
* The engine coolant temperature (ECT) is within 10掳C (18掳F) of the ambient air temperature at engine start.
* The vehicle speed sensor (VSS) is less than 3 km/h (2 mph).
* The above conditions are met for greater than 30 s
* DTC P0455 or DTC P0497 will attempt to run up to 10 times or until the test completes successfully once per ignition cycle.
Conditions for Setting the DTC
* The ECM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test.
* The condition exists for greater than 4 s or for a cumulative of 30 s.
Action Taken When the DTC Sets
DTCs P0455 and P0497 are Type A/B DTCs.
Conditions for Clearing the DTC
DTCs P0455 and P0497 are Type A/B DTCs.
