DTC P0638 Throttle Actuator Control Range/Performance (4JJ3 without DPD)

Note

  • This DTC may be set if the intake throttle valve is stuck or intermittently stuck.
  • An intake throttle valve stuck at the fully closed position will cause an engine starting malfunction.

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) Diagnostic system check-engine controls".

2. Prioritized DTC check

1) Connect the scan tool.

2) Turn OFF the ignition switch for 1 minute or more.

3) Start the engine.

4) Observe the DTC information with a scan tool. Is DTC P0122 or P0123 set at the same time?

Yes

Go to the applicable DTC diagnosis.

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) DTC P0122 Throttle Position Sensor Circuit Low".

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) DTC P0123 Throttle Position Sensor Circuit High".

No

=>Go to Intake throttle valve operation check.

3. Intake throttle valve operation check

1) Perform the Intake Throttle with a scan tool.

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

Note

  • Compare with other vehicles having the same engine if possible.

Value: -5 to 5 %

Yes

Go to Intermittent conditions of engine.

Refer to "202.Engine 15D.Symptom(4JJ3 without DPD) intermittent conditions of engine".

No

=>Go to Intake throttle valve inspection.

4. Intake throttle valve inspection

1) Remove the intake air duct from the intake throttle valve.

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.

No

Repair or replace as necessary.

=>Go to Intake throttle valve operation signal input inspection.

5. 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 1, 2, and 25 of E2, and pins18 and 29 of E3). Is the connection status normal?

3) Inspect the circuit between the ECM (pins 1, 2, and 25 of E2, and pins 18 and 29 of E3) and the intake throttle valve (pins 2, 3, 4, 5, and 6 of E25) for high resistance. Is the result normal?

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

4) Are all of the results normal?

Yes

=>Go to Inspection for open circuit and short circuit in intake throttle motor circuit.

No

Repair the circuit or connection as necessary.

=>Go to Intake throttle valve operation signal input inspection.

6. Inspection for open circuit and short circuit in intake throttle motor circuit

1) Inspect the motor circuit between the ECM (pins 1 and 2 of E2) and the intake throttle valve (pins 5 and 6 of E25) for the following. Is the result normal?

  • Open circuit
  • Short to the battery power supply circuit or short to the ignition power supply circuit
  • Short to ground
  • Short together between motor circuits
  • Short to intake throttle position sensor circuit
  • High resistance

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

Replace the intake throttle valve.

Refer to "1.Engine 1B.Mechanical(4JJ3 without DPD) Intake throttle valve removal".

Refer to "1.Engine 1B.Mechanical(4JJ3 without DPD) Intake throttle valve installation".

=>Go to Repair verification.

No

Repair the circuit as necessary.

=>Go to Intake throttle valve operation signal input inspection.

7. Intake throttle valve operation signal input inspection

1) Reconnect all of the disconnected harness connectors.

2) Clear the DTC with a scan tool.

3) Turn OFF the ignition switch for 1 minute or more.

4) Start the engine.

5) Operate the vehicle under the conditions for running the DTC.

6) Observe the DTC information with a scan tool. Is a DTC set?

Yes

=>Go to ECM replacement.

No

=>Go to Repair verification.

8. ECM replacement

Note

  • Perform programming after replacing the ECM.

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM setting".

Procedure completion

=>Go to Repair verification.

9. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 1 minute or more.

3) Start the engine.

4) Operate the vehicle under the conditions for running the DTC.

5) Observe the DTC information with a scan tool.