P0430

SYMPTOM
P0430 CATALYTIC 2/1 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 in. Hg.

SET CONDITION
As catalyst efficiency deteriorates, the switch rate of the downstream 02 sensor approaches that of the upstream 02 sensor. If at any point during the test the switch ratio reaches a predetermined value a counter is incremented by one. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- EXHAUST LEAK
- ENGINE MECHANICAL CONDITION
- AGING 02 SENSOR
- CATALYTIC CONVERTER

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Scan Tool Testing and Procedures

DIAGNOSTIC TEST
1. ACTIVE DTC





Note: A new rear 02 Sensor along with an aging front 02 Sensor may cause the DTC to set. Review the repair history of the vehicle before continuing.

Note: If an 02 Sensor DTC set along with the Catalytic Converter Efficiency DTC diagnose the 02 Sensor DTC(s) before continuing.

Note: Check for contaminants that may have damaged the 02 Sensor and Catalytic Converter: contaminated fuel, unapproved silicone, oil and coolant, repair necessary. Ignition on, engine not running.

With a scan tool, read DTCs.
Is the DTC active at this time?
Yes>> Go To 2
No>> Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5. Powertrain Verification Test - Ver 5

2. VISUALLY INSPECT CATALYTIC CONVERTER
Inspect the Catalytic Converter for the following damage.
Damage Catalytic Converter, dents or 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 have caused the failure. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 3

3. EXHAUST LEAK
Start the engine.
Inspect the exhaust for leaks between the engine and the 2/1 02 Sensor.
Inspect the exhaust for leaks between the engine and the 2/2 02 Sensor.
Are there any exhaust leaks?
Yes>> Repair or replace the leaking exhaust parts as necessary. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 4

4. ENGINE MECHANICAL CONDITION
Check the exhaust for excessive smoke caused by an internal problem in the engine.
Is an engine mechanical condition present?
Yes>> Repair the engine mechanical condition as necessary. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 5

5. AGING 02 SENSOR
A new rear 02 Sensor along with an aging front 02 Sensor may cause the DTC to set.
Review the vehicles repair history.
Has the rear 02 Sensor been replaced without replacing the front 02 Sensor?
Yes>> Replace the 2/1 02 Sensor as necessary. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 6

6. CATALYTIC CONVERTER
If there are no possible cause remaining, view repair.
Repair
Replace the Catalytic Converter. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.