Chrysler 2005 Crossfire SRT6 Service Manual page 4302

EMISSIONS CONTROL 25 - 9
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The leak test consists of three successive tests that are dependent on the previous test passing. If one test fails, the
next test will not be run. The major leak test begins by closing the Charcoal Canister Shutoff Valve and opening the
EVAP Purge Solenoid to allow engine vacuum to build to 6 mbar (2.4 inH2O), as measured by the Fuel Tank Pres-
sure Sensor, in the fuel tank within approximately 12 seconds. If there is no vacuum buildup in the fuel tank, there
is a major leak present, the leak test is aborted, the Low Fuel Warning Indicator is illuminated in the instrument
cluster and a DTC is stored in the PCM.
If the major leak test passes, the EVAP Purge Solenoid is closed when vacuum inside the fuel tank reaches approx-
imately 6 mbar (2.4 inH2O) and the vacuum is analyzed for approximately 30 seconds. The vacuum must not drop
by more than 0.3 to 0.5 mbar (0.12 to 0.2 inH2O), depending on the fuel level in the fuel tank, during the 30 second
time period. If there is a minor leak, the leak test is aborted and a DTC is stored in the PCM. The leak test will be
aborted if an excessive lean correction occurs during vacuum buildup.
If the minor leak test passes, the micro leak test initiates by again bringing the vacuum in the fuel tank up to approx-
imately 6 mbar (2.4 inH2O). Once the vacuum in the fuel tank is re-established, the EVAP Purge Solenoid is closed.
The vacuum must not drop by more than 0.1 to 0.15 mbar (0.04 to 0.06 inH2O), depending on the fuel level in the
fuel tank, per second. If the vacuum drops more rapidly, a DTC is stored in the PCM. The leak test will be aborted
if an excessive lean correction occurs during vacuum buildup.
When the leak test is complete, the EVAP Purge Solenoid is opened and the purge control system returns to normal
operation.
DESCRIPTION - NON-MONITORED CIRCUITS
The PCM does not monitor all circuits, systems and conditions that could have malfunctions causing driveability
problems. However, malfunctions in these systems may cause the PCM to store diagnostic trouble codes for other
systems or components. For example, a fuel pressure problem will not register a fault directly but could cause a
rich/lean condition or misfire. This could cause the PCM to store an oxygen sensor or misfire diagnostic trouble
code.
The major non-monitored circuits are listed below along with examples of failure modes that do not directly cause
the PCM to set a DTC, but instead for a system that is monitored.
FUEL PRESSURE
The fuel pressure regulator controls fuel system pressure. The PCM cannot detect a clogged fuel pump inlet filter,
clogged in-line fuel filter, or a pinched fuel supply or return line. However, these could result in a rich or lean con-
dition causing the PCM to store an oxygen sensor, fuel system, or misfire diagnostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil, fouled or worn spark plugs, ignition cross firing, or open spark
plug cables. The misfire will, however, increase the oxygen content in the exhaust, deceiving the PCM into thinking
the fuel system is too lean. Also see misfire detection.
CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine cylinder compression. Low compression lowers O2 content in
the exhaust, leading to a fuel system, oxygen sensor or misfire detection fault.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or leaking exhaust system. It may set an EGR, Fuel system or O2S
fault.
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The PCM cannot determine if a fuel injector is clogged, the needle is sticking or if the wrong injector is installed.
However, these could result in a rich or lean condition causing the PCM to store a diagnostic trouble code for either
misfire, an oxygen sensor or the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen content when the system is in closed loop, it cannot determine
excessive oil consumption.