EGR control system check (RZ4E-TC)

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".

2. Prioritized DTC check

1) Connect the scan tool.

2) Turn OFF the ignition switch for 30 seconds or more.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool. Is the DTC to inhibit the EGR control set?

Yes

Go to the applicable DTC diagnosis.

=>Go to EGR components inspection.

3. EGR components inspection

1) Inspect for the following. Is the result normal?

Missing or damaged EGR valve gasket
Stuck EGR valve
EGR gas leakage from the EGR passage between the exhaust manifold and the inlet manifold
Collapsed or restricted flow in the EGR passage between the exhaust manifold and the EGR valve
Conditions that restrict exhaust system flow
Clogged air cleaner element, collapsing of the air intake piping between the air cleaner and inlet manifold, or a state where flow is restricted
Leakage in the air intake system
Water in the air intake system
Dirt or foreign material blocking the inlet of the MAF sensor
Misdetection or delayed response of the MAF sensor
Engine coolant temperature sensor malfunction

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) engine coolant temperature sensor inspection".

Barometric pressure sensor malfunction

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) barometric pressure sensor inspection".

Stuck intake throttle valve

Yes

=>Go to EGR valve operation check.

Repair as necessary.

=>Go to Repair verification.

4. EGR valve operation check

1) Set the shift lever to the neutral position and apply the parking brake.

2) Start the engine.

3) While observing the Desired Exhaust Gas Recirculation (EGR) Valve Position parameter and Exhaust Gas Recirculation (EGR) Valve Position parameter on the scan tool, depress the accelerator pedal from idle to full throttle several times. Is the difference between the Exhaust Gas Recirculation (EGR) Valve Position parameter and the Exhaust Gas Recirculation (EGR) Valve Position parameter within the specified range?

Value: -5 to 5 %

Yes

=>Go to EGR valve operation check using scan tool.

=>Go to EGR valve inspection.

5. EGR valve operation check using scan tool

1) Perform the EGR Valve with a scan tool.

2) While observing the Desired Exhaust Gas Recirculation (EGR) Valve Position parameter and Exhaust Gas Recirculation (EGR) Valve Position parameter on the scan tool, command the EGR Valve INCREASE/DECREASE. Is the difference between the Exhaust Gas Recirculation (EGR) Valve Position parameter and the Exhaust Gas Recirculation (EGR) Valve Position parameter within the specified range?

Value: -5 to 5 %

Yes

=>Go to Intake throttle valve operation check.

=>Go to EGR valve inspection.

6. Intake throttle valve operation check

1) Observe the Desired Intake Throttle Valve Position parameter and Intake Throttle Valve Position parameter on the scan tool. Is the difference between the Desired Intake Throttle Valve Position parameter and the Intake Throttle Valve Position parameter within the specified range?

Note

The Intake Throttle Valve Position parameter shows the values of 100% or more when the intake throttle motor is OFF.

Value: -5 to 5 %

Yes

=>Go to Intake throttle valve operation check using a scan tool.

=>Go to Intake throttle valve inspection.

7. Intake throttle valve operation check using a scan tool

1) Perform the Intake Throttle Valve with a scan tool.

2) While observing the Desired Intake Throttle Valve Position parameter and Intake Throttle Valve Position parameter on the scan tool, command the intake throttle valve INCREASE/DECREASE. Is the difference between the Desired Intake Throttle Valve Position parameter and the Intake Throttle Valve Position parameter within the specified range?

Value: -5 to 5 %

Yes

The system is normal.

=>Go to Intake throttle valve inspection.

8. EGR valve inspection

1) Remove the EGR valve from the engine.

Refer to "1.Engine 1H.Aux. Emission Control Devices(RZ4E-TC) EGR removal".

2) Inspect the EGR valve for the following. Is the result normal?

The flow in the EGR valve is restricted by foreign material.
Excessive deposits in the valve
Bent valve shaft or valve

Yes

=>Go to Inspection of EGR valve circuit.

Repair or replace as necessary.

=>Go to Repair verification.

9. Inspection of EGR valve circuit

1) Inspect for poor connections at the EGR valve harness connector (pins 1, 2, 3, 4, and 6 of E49). Is the connection status normal?

2) Inspect for poor connections at the ECM harness connector (pins 11, 14, 22, 28, and 30 of E4). Is the connection status normal?

3) Inspect the circuit between the ECM (pins 11, 14, 22, 28, and 30 of E4) and the EGR valve (pins 1, 2, 3, 4, and 6 of E49) for high resistance. Is the result normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

4) Are all of the results normal?

Yes

Replace the EGR valve.

Refer to "1.Engine 1H.Aux. Emission Control Devices(RZ4E-TC) EGR removal".

Refer to "1.Engine 1H.Aux. Emission Control Devices(RZ4E-TC) EGR installation".

=>Go to Repair verification.

Repair the circuit or connection as necessary.

=>Go to Repair verification.

10. Intake throttle valve inspection

1) Remove the intake throttle valve.

Refer to "1.Engine 1B.Mechanical(RZ4E-TC) Intake throttle valve removal".

2) Inspect the intake throttle valve for the following. Is the result normal?

The flow in the intake throttle valve is restricted by foreign material.
Excessive deposits inside the throttle
Bent butterfly valve

Note

If sticking exists, replace the intake throttle valve.

Yes

=>Go to Intake throttle valve circuit inspection.

Repair or replace as necessary.

=>Go to Repair verification.

11. Intake throttle valve circuit inspection

1) Inspect for poor connections at the intake throttle valve harness connector (pins 2, 3, 4, 5, and 6 of E25). Is the connection status normal?

2) Inspect for poor connections at the ECM harness connector (pins 4, 14, 23, 28, and 31 of E4). Is the connection status normal?

3) Inspect the circuit between the ECM (pins 4, 14, 23, 28, and 31 of E4) and the intake throttle valve (pins 2, 3, 4, 5, and 6 of E25) for high resistance. Is the result normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

4) Are all of the results normal?

Yes

Replace the intake throttle valve.

Refer to "1.Engine 1B.Mechanical(RZ4E-TC) Intake throttle valve removal".

Refer to "1.Engine 1B.Mechanical(RZ4E-TC) Intake throttle valve installation".

=>Go to Repair verification.

Repair the circuit or connection as necessary.

=>Go to Repair verification.

12. Repair verification

1) Reconnect all of the disconnected harness connectors and components.

Procedure completion

=>Go to EGR valve operation check.