Chrysler 1997 Stratus Convertible RHD Service Manual page 1190

STEM PROTECTOR EGR VALVE DIA- P HRAGM PISTON MOVEMENT SCREW (2) BASE INDICATOR AND BUSHING EGR SPRING ASSEMBLY EXHAUST THERMOSTAT VALVE EGR VACUUMMOTOR HOUSING VALVE GAS EXHAUST INLET MOTOR FITTING VACUUM FITTING VACUUM GAS SURE FITTING OUT-
25 - 24 EMISSION CONTROL SYSTEMS
DESCRIPTION AND OPERATION (Continued)
Fig. 3 EGR Valve—2.5L
Fig. 4 Electric EGR Transducer
valve. Varying the strength of the vacuum changes
the amount of EGR supplied to the engine. This pro-
vides the correct amount of exhaust gas recirculation
for different operating conditions.
POPPET LET BACK-PRES- EGR TO TROL ASSEMBLY SEAT VALVE OUTLET VALVE VALVE CONNECTION ELECTRICAL EGR CON- POINT TION TRANSDUCER POR- TION OF VALVE SOLENOID POR- ELECTRIC VACUUM INLET FITTING OF EGR VALVE CONTROL CONTROL VALVE FROM ENGINE PRESSURE BACK- EGR TUBE HOSE
This system does not allow EGR at idle.
A failed or malfunctioning EGR system can cause
engine spark knock, sags or hesitation, rough idle,
engine stalling and increased emissions.
DIAGNOSIS AND TESTING
EGR SYSTEM ON-BOARD DIAGNOSTICS
The PCM performs an on-board diagnostic check of
the EGR system. The diagnostic system uses the
electronic EGR transducer for the system tests.
The diagnostic check activates only during selected
engine/driving conditions. When the conditions are
met, the PCM energizes the transducer solenoid to
disable the EGR. The PCM checks for a change in
the heated oxygen sensor signal. If the air-fuel mix-
ture goes lean, the PCM will attempt to enrichen the
mixture. The PCM registers a Diagnostic Trouble
Code (DTC) if the EGR system has failed or
degraded. After registering a DTC, the PCM turns on
the malfunction indicator (Check Engine) lamp. The
Malfunction Indicator Lamp (MIL) indicates the need
for service.
If a problem is indicated by the MIL and a DTC for
the EGR system is set, check for proper operation of
the EGR system. Use the System Test, EGR Gas Flow
Test and EGR Diagnosis Chart. If the EGR system
tests properly, check the system using the DRB scan
tool. Refer to On-Board Diagnosis sections in this
Group. Also, refer to the DRB scan tool and the appro-
priate Powertrain Diagnostics Procedure manual.
EGR SYSTEM ON-BOARD DIAGNOSTICS
The PCM performs an on-board diagnostic check of
the EGR system. The diagnostic system uses the
electronic EGR transducer for the system tests.
The diagnostic check activates only during selected
engine/driving conditions. When the conditions are
met, the PCM energizes the transducer solenoid to
disable the EGR. The PCM checks for a change in
the heated oxygen sensor signal. If the air-fuel mix-
ture goes lean, the PCM will attempt to enrichen the
mixture. The PCM registers a Diagnostic Trouble
Code (DTC) if the EGR system has failed or
degraded. After registering a DTC, the PCM turns on
the malfunction indicator (Check Engine) lamp. The
Malfunction Indicator Lamp (MIL) indicates the need
for service.
If a problem is indicated by the MIL and a DTC for
the EGR system is set, check for proper operation of
the EGR system. Use the System Test, EGR Gas Flow
Test and EGR Diagnosis Chart. If the EGR system
tests properly, check the system using the DRB scan
tool. Refer to On-Board Diagnosis sections in this
Group. Also, refer to the DRB scan tool and the appro-
priate Powertrain Diagnostics Procedure manual.
JX