Code No. P0403: EGR Valve DC Motor Malfunction
OPERATION
- The electric current from the engine-ECU connector terminal EGR+ and
EGR- to the EGR valve (DC motor) connector terminal is controlled.
FUNCTION
- The engine-ECU performs duty control over the EGR valve (DC motor).
- The engine-ECU performs feedback control over the EGR valve based on the signals
from the EGR position sensor.
TROUBLE JUDGMENT
Check Condition
- Ignition switch is in "ON" position
- An over current cut-off signal from the EGR valve drive control integrated circuit
(IC) is detected.
FAIL-SAFE AND BACKUP FUNCTION
- The DPF regeneration is prohibited.
- The throttle valve is opened (Electrical discontinuity).
- The EGR control is stopped (fully closed).
- The AS&G control is prohibited.
PROBABLE CAUSES
- Failed EGR valve
- Open/short circuit or harness damage in EGR valve circuit or loose connector contact
- Failed engine-ECU
DIAGNOSIS PROCEDURE |
STEP 1. Check EGR valve itself. |
Q.
Is the check result normal?
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Go to Step 2. |
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Repair or replace the connector, or replace the EGR valve assembly. |
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STEP 2. Check harness between engine-ECU connector terminal EGR+ and EGR valve assembly connector terminal. |
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Q.
Is the check result normal?
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Go to Step 3. |
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Repair or replace the connector, or repair the damaged harness wire. |
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STEP 3. Check harness between engine-ECU connector terminal EGR- and EGR valve connector terminal. |
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Q.
Is the check result normal?
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Go to Step 4. |
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Repair or replace the connector, or repair the damaged harness wire. |
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STEP 4. M.U.T.-III diagnosis code |
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Q.
Is the diagnosis code set?
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Replace the engine-ECU. |
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ). |
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