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Home >> Suzuki >> 2007 >> Grand Vitara Base, RWD, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine General Information And Diagnosis >> Diagnostic Information And Procedures >> DTC P0401/P0402: Exhaust Gas Recirculation Flow Insufficient Detected/Excessive Detected >> DTC Troubleshooting

DTC Troubleshooting

NOTE: Before this trouble shooting is performed, read the precautions for DTC troubleshooting, referring to PRECAUTIONS FOR DTC TROUBLESHOOTING .
TROUBLESHOOTING TABLE

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  Do you have SUZUKI scan tool?  Go to Step 3. Go to Step 5.
3  EGR valve operation check 
  1. With ignition switch OFF, install SUZUKI scan tool.
  2. Check EGR system, referring to EGR SYSTEM INSPECTION (USING SUZUKI SCAN TOOL) .

Is it in good condition? 		 Go to Step 4. Go to Step 5.
4  MAP sensor check 
  1. Check MAP sensor for performance, referring to MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION .

Is check result satisfactory? 		 Intermittent trouble or faulty ECM.
Check for intermittent and poor connection.		 Replace MAP sensor.
5  EGR valve control circuit check 
  1. Check that EGR valve control circuits are in good condition, referring to step 3 of DTC P0403: EXHAUST GAS RECIRCULATION CONTROL CIRCUIT .

Are circuits in good condition? 		 Go to Step 6. Repair or replace EGR valve control circuit(s).
6  EGR valve check 
  1. Check EGR valve, referring to PCV VALVE INSPECTION .

Is check result satisfactory? 		 Go to Step 7. Faulty EGR valve.
7  MAP sensor check 
  1. Check MAP sensor for performance, referring to MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION .

Is check result satisfactory? 		 EGR passage clogged. If OK, substitute a known good ECM and recheck. Replace MAP sensor.
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