DTC P0638

BHE010200600W05

DTC P0638

Throttle actuator control circuit range/performance problem

DETECTION CONDITION

• The PCM compares the actual TP with the target TP when the engine is running. If the difference is more than the specification, the PCM determines that there is a throttle actuator control circuit range/performance problem.

Diagnostic support note

• This is a continuous monitor (CCM).
• The MIL illuminates if the PCM detects the above malfunction condition in the first drive cycle.
• PENDING CODE is available if the PCM detects the above malfunction condition.
• FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• Drive-by-wire control system malfunction
• Throttle actuator malfunction
• Throttle valve malfunction
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2

VERIFY RELATED REPAIR INFORMATION AVAILABILITY

• Verify related service repair information availability.
• Is any related repair information available?
Yes
Perform repair or diagnosis according to the available repair information.
• If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3

VERIFY RELATED PENDING CODE OR STORED DTC

• Turn the ignition switch off, then to the ON position (Engine off).
• Verify the related PENDING CODE or stored DTCs.
• Are other DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE.)
No
Go to the next step.
4

INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION

• Perform the "Drive-by-wire Control System Inspection".
• Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
Then go to Step 7.
No
Go to the next step.
5

INSPECT THROTTLE ACTUATOR

• Inspect the throttle actuator.
• Is there any malfunction?
Yes
Replace the throttle body, then go to Step 7.
No
Go to the next step.
6

INSPECT THROTTLE VALVE

• Inspect the throttle valve.
• Is there any malfunction?
Yes
Replace the throttle body, then go to the next step.
No
Go to the next step.
7

VERIFY TROUBLESHOOTING OF P0638 COMPLETED

• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Start the engine.
• Is the same DTC present?
Yes
Replace the PCM, go to the next step.
No
Go to the next step.
8

VERIFY AFTER REPAIR PROCEDURE

• Perform the "AFTER REPAIR PROCEDURE".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE.)
No
DTC troubleshooting completed.