Code No. P2426: EGR Cooling Valve Control Circuit (Low)
OPERATION
- Power is supplied to the EGR cooler bypass control solenoid valve connector terminal from the engine control relay connector terminal.
- The engine-ECU connector terminal EGC makes the power transistor in the unit be in "ON" position, and that makes currents go on the EGR cooler bypass control solenoid valve connector terminal.
FUNCTION
- By the signals from the engine-ECU, the EGR cooler bypass control solenoid valve takes control switching the pressure in the vacuum pump between the vacuum pressure and the atmospheric pressure.
TROUBLE JUDGEMENT
Check Conditions
- Battery positive voltage is 8 - 16 V.
- 2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
Judgement Criterion
- When the ECU command is "OPEN" and the valve position judged by the terminal voltage is "CLOSED".
FAIL-SAFE AND BACKUP FUNCTION
- The EGR control is stopped (fully closed).
PROBABLE CAUSES
- Failed EGR cooler bypass control solenoid valve
- Open/short circuit or harness damage in EGR cooler bypass control solenoid valve circuit or loose connector contact
- Failed engine-ECU
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STEP 1. M.U.T.-III actuator test
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- Item 31: EGR cooler bypass control solenoid valve
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OK: Operating sound can be heard and the valve vibrates
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Q.
Is the check result normal?
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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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 Go to Step 2.
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STEP 2. Resistance measurement at EGR cooler bypass control solenoid valve connector.
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(1)Disconnect the connector, and measure at the sensor side.
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(2)Measure the resistance between terminals.
OK: 29 - 35 Ω (at 20°C)
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Q.
Is the check result normal?
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Go to Step 3.
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Replace the EGR cooler bypass control solenoid valve.
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STEP 3. Voltage measurement at EGR cooler bypass control solenoid valve connector (power supply line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the EGR cooler bypass control solenoid valve connector (power supply line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 4.
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Repair power supply line between engine control relay connector and EGR cooler bypass control solenoid valve connector.
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STEP 4. Voltage measurement at engine-ECU connector (EGC line).
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(1)Disconnect connector, and measure at harness side.
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(3)Check the voltage between the engine-ECU connector (EGC line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 5.
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Repair EGC line between EGR cooler bypass control solenoid valve connector and engine-ECU connector.
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STEP 5. Check of damage in EGC line between EGR cooler bypass control solenoid valve connector and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 6.
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Repair the connector(s) or wiring harness.
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STEP 6. Check of damage in power supply line between engine control relay connector and EGR cooler bypass control solenoid valve connector.
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Q.
Is the check result normal?
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Go to Step 7.
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Repair the connector(s) or wiring harness.
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STEP 7. M.U.T.-III actuator test
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- Item 31: EGR cooler bypass control solenoid valve
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OK: Operating sound can be heard and the valve vibrates
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Q.
Is the check result normal?
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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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Replace the engine-ECU.
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