Chrysler 300M 2002 Service Manual page 2596

P0420-CATALYTIC 1/1 EFFICIENCY —
TEST
1 NOTE: If a O2 Sensor DTC(s) set along with the Catalytic Converter
Efficiency DTC diagnose the O2 Sensor DTC(s) before continuing.
NOTE: Check for contaminates that may have damaged the O2 Sensor and
Catalytic Converter: contaminated fuel, unapproved silicone, oil and cool-
ant, repair necessary.
Ignition on, engine not running.
With the DRBIII , read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
Yes → Go To 2
→ Go To 7
No
2 Inspect the Catalytic Converter for the following damage.
Damage Catalytic Converter, dent and holes.
Severe discoloration caused by overheating the Catalytic Converter.
Catalytic Converter broke internally.
Leaking Catalytic Converter.
Were any problems found?
Yes → Replace the Catalytic Converter. Repair the condition that may
→ Go To 3
No
3 Start the engine.
Inspect the exhaust for leak between the engine and the O2 Sensor.
Inspect the exhaust for leaks between the engine and the appropriate rear O2 Sensor.
Are there any exhaust leaks?
Yes → Repair or replace the leaking exhaust parts as necessary.
→ Go To 4
No
4 Check the exhaust for excessive smoke caused by an internal problem in the engine.
Is a engine mechanical condition present?
Yes → Repair the engine mechanical condition as necessary.
→ Go To 5
No
5 A new rear O2 Sensor along with an aging front O2 Sensor may cause the DTC to set.
Review the vehicles repair history.
Has the rear O2 Sensor been replace without replacing the front O2 Sensor?
Yes → Replace the Front O2 Sensor as necessary.
→ Go To 6
No
6 If there are no possible cause remaining, view repair.
Repair
ACTION
have caused the failure.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Replace the Catalytic Converter.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
DRIVEABILITY - NGC
Continued
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APPLICABILITY
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