LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2005 >> Aerio LX, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine General Information And Diagnosis >> DTC P0420: Catalyst System Efficiency below Threshold >> Diagnostic Trouble Codes Troubleshooting
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Trouble Codes Troubleshooting

DTC TROUBLESHOOTING

Step Action Yes No
1 Was "Engine and Emission Control System Check" performed?  Go To Step 2. Go to "ENGINE AND EMISSION CONTROL SYSTEM CHECK :".
2 Exhaust system visual inspection 
  1. Check exhaust system for leaks, damage and loose connection.

Is it in good condition? 		 Go To Step 3. Repair or replace.
3 HO2S-2 output voltage check 
  1. Check output voltage of HO2S-2 referring to "DTC P0137 / P0138: 02 SENSOR CIRCUIT LOW / HIGH VOLTAGE (SENSOR-2) :".

Is check result satisfactory? 		 Replace three way catalytic converter. Check "WHT" and "ORN" wires for open and short, and connections for poor connection.
If wires and connections are OK, replace HO2S-2.
scientia non olet · About LEMON Manuals