DTC P0420, P0430 [MZI-3.7]
DTC P0420, P0430 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES
9
INSPECT IGNITION COIL
z
Inspect ignition coil. (See
IGNITION
COIL INSPECTION [MZI-3.7]
.)
z
Are there ignition coil normal?
Yes Go to the next step.
No
Replace the ignition coil, then go to the next
step.
10
VERIFY TROUBLESHOOTING OF
DTC P0351, P0352, P0353, P0354, P0355
and P0356 COMPLETED
z
Verify that all disconnected connectors
reconnected.
z
Clear the DTC from the PCM memory
using the M-MDS.
z
Perform the "KOEO or KOER self-
test" using the M-MDS. (See
KOEO/KOER SELF TEST [MZI-
3.7]
.)
z
Is the PENDING CODE for the DTC
present?
Yes
Replace the PCM, then go to the next step. (See
PCM REMOVAL/INSTALLATION [MZI-
3.7]
.)
No
Go to the next step.
11
VERIFY AFTER REPAIR PROCEDURE
z
Perform "AFTER REPAIR
PROCEDURE". (See
AFTER
REPAIR PROCEDURE [MZI-3.7]
.)
z
Are any DTCs present?
Yes
Go to the applicable DTC inspection. (See
DTC
TABLE [MZI-3.7]
.)
No
Troubleshooting completed.
DTC P0420 P0420: Catalyst system efficiency below threshold (RH)
DTC P0430 P0430: Catalyst system efficiency below threshold (LH)
DETECTION
CONDITION
z
P0420 indicates right bank catalyst system efficiency is below the acceptable
threshold.
z
P0430 indicates left bank catalyst system efficiency is below the acceptable
threshold.
z
Use of leaded fuel.
z
Oil contamination
z
Cylinder misfiring.
z
Damaged HO2S.
z
Malfunctioning CHT sensor.
z
Downstream HO2S wires improperly connected.
z
Fuel pressure too high.
2008 Mazda CX-9 Grand Touring
2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9
Microsoft
Sunday, November 15, 2009 10:08:37 AM
Page 198
© 2005 Mitchell Repair Information Company, LLC.
