Aveo L4-1.6L (2008)
Oxygen Sensor: Customer Interest
Fuel System - MIL ON/DTC's P0420/P0133/P0131
TECHNICAL
Bulletin No.: 08-06-04-027B
Date: December 13, 2010
Subject: EI08145 - Check Engine Light Illuminated, DTC P0420 Catalyst System Low Efficiency, O2 Lean Limit Code P0131, P0133 (Replace All
Injectors)
Models:
2004-2008 Chevrolet Aveo
2005-2008 Pontiac Wave (Canada Only)
Equipped With 1.6L Engine (VIN 6 - RPO L91, LXT)
Supercede:
This bulletin is being revised to update diagnostics information. Please discard Corporate Bulletin Number 08-06-04-027A (Section 06 -
Engine/Propulsion System).
Condition
Some customers may comment that the check engine light is illuminated. Upon investigation, the technician may find DTC P0420 stored, possibly
accompanied by an O2 lean limit code of P0131 or P0133.
Cause
This condition may be caused by the rear O2 sensor not tracking the front O2 sensor within the calibration limits during the Catalyst Efficiency test. The
DTC may be the result of improper fuel, fuel mixture, fuel balance, exhaust leaks, damaged wiring, O2 contamination or, in rare cases, a damaged
catalytic converter.
Correction
Important
DO NOT replace the catalytic converter unless conclusive converter damage is present.
1. Follow P0420 diagnostics per SI. If diagnostics lead to a repair other than catalytic converter replacement, then proceed to Step 3 after the repair
has been completed. If SI diagnostics lead to a catalytic converter replacement, proceed to Step 2.
2. Replace all four fuel injectors if no cause of the P0420 was found using SI diagnostics, or if SI diagnostics led to catalytic converter replacement.
After replacing all four fuel injectors, continue to Step 3.
3. Disconnect the battery for two minutes. The battery disconnect will reset the ECM NVM (non-volatile memory), causing a default run cycle of the
catalyst monitor event. The ECM will run the event up to six consecutive times during the test drive as described in step 7 below. The ECM will
repeat the six consecutive run events once more after the key has been cycled off and back on.
4. Connect a Tech 2(R) and clear all DTCs.
5. Plan to test drive the vehicle for approximately 20 minutes to capture the catalyst monitoring event by following the Tech 2(R) driving instructions
below. Refer to Corporate Bulletin Number 07-07-30-010B for information on the process of taking, uploading and e-mailing snap shots via
TIS2WEB.
6. Prepare the Tech 2(R) for a test drive Snap Shot. With the vehicle running at idle in Park, set the Tech 2(R) for:
-
Manual Trigger
-
Center Snapshot
-
Select Engine Data for Air Fuel Ratio, Front O2 Sensor, Rear O2 Sensor and Engine Run Time
7. Test drive the vehicle under light to moderate throttle to meet the following enable criteria:
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Exceed ten minutes engine run time as shown on the Tech 2(R).
-
Exceed 48 km/h (30 mph) for at least fifteen consecutive seconds.
-
Stop the vehicle and remain in drive position (neutral for manual transmission) for at least 60 seconds.
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Monitor the Tech 2(R). The air fuel ratio will exceed 14.7:1 to approximately 16.2:1 and then drop below 14.7:1 to approximately 13.4:1 and
then stabilize at 14.7:1.
-
Capture this event by starting the snap shot with the manual trigger (center trigger).
8. Continue to test drive the vehicle repeating step 7 five more times.
