2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1349
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1) ()
* Catalytic Converter Replacement - Left Side (LF1) ()
* Catalytic Converter Replacement - Right Side (LF1) ()
P0442
DTC P0442
Diagnostic Instructions
* 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 P0442
- Evaporative Emission System Small Leak Detected
Circuit/System Description
The engine off natural vacuum test is the small leak detection diagnostic for the evaporative emission system. This diagnostic tests the evaporative
emission system for a small leak when the key is turned OFF and the correct conditions are met. Heat from the exhaust system is transferred into
the fuel tank while the vehicle is operating. When the vehicle is turned OFF and the evaporative emission system is sealed a change in the fuel tank
vapor temperature occurs which results in a corresponding pressure change in the fuel tank vapor space. This change is monitored by the ECM
using the fuel tank pressure sensor input. With a leak in the system, the amount of pressure change will be less than that of a sealed system.
Conditions for Running the DTC
* DTCs P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0222, P0223, P0443, P0446, P0449,
P0451, P0452, P0453, P0454, P0455, P0461, P0462, P0463, P0464, P0496, P0502, P0503, P0608, P0641, P0651, P1516, P2101, P2119,
P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.
* The ignition 1 voltage is between 10-16 V.
* The barometric pressure (BARO) is greater than 74 kPa.
* No fuel filling during the engine off natural vacuum test period.
* The fuel level is between 10-90 percent.
* The start-up engine coolant temperature (ECT) and the start-up intake air temperature (IAT) are between 0-40掳C (32-104掳F).
* The barometric pressure (BARO) is more than 74 kPa.
* The engine run time before engine shut-off was greater than 10 minutes.
* The drive distance before engine shut-off was more than 5 kilometers (3.1 miles).
* The ignition is OFF.
* The ambient air temperature at the end of the drive cycle is between 0-32掳C (32-93掳F).
* DTC P0442 runs once per drive cycle during the hot soak period after the ignition is turned OFF and may require up to 45 minutes to
complete. The controller will not make more than 2 test attempts per day. The time since the last completed engine off natural vacuum test
must be at least 17 hours
Conditions for Setting the DTC
* The ECM detects a leak in the evaporative emission system that is greater than a calibrated amount.
* The ECM must complete several engine off natural vacuum tests before the diagnostic can turn the MIL on or off.
Action Taken When the DTC Sets
DTC P0442 is a Type A DTC.
Conditions for Clearing the DTC
DTC P0442 is a Type A DTC.
Diagnostic Aids
* The evaporative emission system can be filled with smoke more quickly and completely by opening the system opposite the end where the
smoke is injected. When injecting smoke at the service port remove the fuel fill cap, or temporarily leave the vent open, until smoke is
observed then close the system and continue testing.
* To help locate intermittent leaks using the J 41413-200 - EEST , move all evaporative emission components while observing smoke with the
J 41413-SPT - White Light.
