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Home >> Suzuki >> 2007 >> Aerio Base, AWD >> 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 / Excessive Detected >> DTC Troubleshooting

DTC Troubleshooting

DIAGNOSIS PROCEDURE

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 turned OFF, connect SUZUKI scan tool to DLC.
  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. Check for intermittent referring to INTERMITTENT AND POOR CONNECTION INSPECTION . If OK, substitute a known-good ECM and recheck. Repair or replace.
5  EGR valve power supply circuit check 
  1. With ignition switch turned OFF, disconnect EGR valve connector.
  2. With ignition switch turned ON, check voltage between "BLK/RED" wire terminals of EGR valve connector and engine ground.

Is each voltage 10 - 14 V? 		 Go to Step 6. Open wire in "BLK/RED" circuit.
6  Check wire circuit 
  1. Measure voltage between engine ground and each "GRY", "GRY/WHT", "GRY/YEL", "BRN/WHT" wire terminals of EGR valve connector.

Is each voltage 0 V? 		 Go to Step 7. Some wire shorted to other circuits.
If wires are OK, substitute a known-good ECM and recheck.
7  Check wire circuit 
  1. With ignition switch turned OFF, check that there are insulating between engine ground and each "GRY", "GRY/WHT", "GRY/YEL", "BRN/WHT" wire terminals of EGR valve connector.

Are there insulating? 		 Go to Step 8. Some wire shorted to ground circuit.
If wires are OK, substitute a known-good ECM and recheck.
8  EGR valve stepping motor coil circuit check 
  1. With ignition switch turned OFF, connect EGR valve connector and disconnect ECM connectors.
  2. Measure resistance between "G04-7 (or 6) terminal of ECM connector and "C46-8", "C46-9", "C46-18", "C46- 19" terminals of ECM connector.

Is each resistance 20 - 31 ohm at 20°C, 68°F? 		 Go to Step 9. Faulty "GRY", "GRY/WHT", "GRY/YEL", "BRN/WHT" wire or EGR valve.
9  Check wire circuit 
  1. Measure voltage between engine ground and each EGR valve connector terminal of "GRY", "GRY/WHT", "GRY/YEL", "BRN/WHT" wire with ignition switch turned ON.

Is each voltage 10 - 14 V? 		 Some wire in high resistance circuit.
If wires are good condition, go to Step 10.		 Open wire in applicable circuit. If wires are good condition, faulty EGR valve.
10  MAP sensor check 
  1. Check MAP sensor for performance referring to MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION .

Is check result satisfactory? 		 EGR passage clogged or EGR valve malfunction, If all results are OK, intermittent trouble or faulty ECM.
Check for intermittent referring to INTERMITTENT AND POOR CONNECTION INSPECTION .		 Repair or replace.
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