Dodge ZB 2005 Service Manual page 1229

DRIVEABILITY - GAS
Symptom List:
P0420-1/1 CATALYTIC CONVERTER EFFICIENCY
P0432-2/1 CATALYTIC CONVERTER EFFICIENCY
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0420-1/1 CATALYTIC CON-
VERTER EFFICIENCY.
When Monitored and Set Condition:
P0420-1/1 CATALYTIC CONVERTER EFFICIENCY
When Monitored: After engine warm up to 147° F, 180 seconds of open throttle operation,
at a speed greater than 20 mph, with the engine at 1200-1700 rpm and MAP vacuum
between 15.0 and 21.0 inches of mercury (Hg).
Set Condition: As catalyst efficiency deteriorates, the switch rate of the downstream O2
sensor approaches that of the upstream O2 sensor. If at any point during the test the
switch ratio reaches a predetermined value a counter is incremented by one.
P0432-2/1 CATALYTIC CONVERTER EFFICIENCY
When Monitored: After engine warm up to 147° F, 180 seconds of open throttle operation,
at a speed greater than 20 mph, with the engine at 1200-1700 rpm and MAP vacuum
between 15.0 and 21.0 inches of mercury (Hg).
Set Condition: As catalyst efficiency deteriorates, the switch rate of the downstream O2
sensor approaches that of the upstream O2 sensor. If at any point during the test the
switch ratio reaches a predetermined value a counter is incremented by one.
GOOD TRIP EQUAL TO ZERO
VISUALLY INSPECT CATALYTIC CONVERTER
EXHAUST LEAK
ENGINE MECHANICAL PROBLEM
UPSTREAM O2 SENSOR OLDER THAN DOWNSTREAM O2 SENSOR
CATALYTIC CONVERTER
TEST
1 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
→ Refer to the INTERMITTENT CONDITION Symptom (Diagnos-
No
POSSIBLE CAUSES
ACTION
tic Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 5.
108
APPLICABILITY
All