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DTC P0638: Throttle Actuator Control Motor Circuit Range/Performance
 
 
 
 
THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE CIRCUIT
  • Refer to DTC P2101 - Throttle Actuator Control Motor Magneto Malfunction .
 
 
CIRCUIT OPERATION
  • Refer to DTC P2101 - Throttle Actuator Control Motor Magneto Malfunction .
 
 
TECHNICAL DESCRIPTION
  • ECM checks the electronic-controlled throttle system for abnormal conditions.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Difference between throttle position sensor (main) output and target opening is greater than the specified value.
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Check Conditions
  • Battery positive voltage is more than 8.3 volts.
  • Throttle position sensor (main) output voltage is between 0.2 and 4.8 volts.
  • Drop of throttle position sensor (main) output voltage per 100 milliseconds is more than -0.04 volt.
Judgment Criterion
  • The target throttle position sensor (main) voltage subtracted from the throttle position sensor (main) output voltage is more than 0.5 volt for 0.4 second.
Check Conditions
  • Battery positive voltage is more than 8.3 volts.
  • Throttle position sensor (main) output voltage is between 0.2 and 4.8 volts.
  • Target throttle position sensor (main) output voltage is less than 1.5 volts.
Judgment Criterion
  • Difference between throttle position sensor (main) output voltage and target throttle position sensor (main) voltage is more than 0.6 volt for 0.4 second.
Check Conditions
  • Battery positive voltage is more than 8.3 volts.
  • Throttle position sensor (main) output voltage is between 0.2 and 4.8 volts.
Judgment Criterion
  • Difference between throttle position sensor (main) output voltage and target throttle position sensor (main) voltage is more than 1 volt for 0.4 second.
Check Condition
  • Battery positive voltage is more than 8.3 volts.
Judgment Criterion
  • Throttle position sensor (main) default opening learnt value is more than 4 volts.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Throttle opening degree position is in default position.
 
 
OBD-II DRIVE CYCLE PATTERN
  • None.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Throttle valve return spring failed.
  • Throttle valve operation failed.
  • Throttle actuator control motor failed.
  • Harness damage in throttle actuator control motor circuit or connector damage.
  • ECM failed.

 
 
DIAGNOSIS
Required Special Tool:
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: V.C.I.
    • MB991827: USB Cable
    • MB991910: Main Harness A
STEP 1. Check harness connector B-12 at electronic-controlled throttle valve for damage.
Is the harness connector in good condition?
Go to Step 2.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 7..
 
STEP 2. Check the throttle actuator control motor.
(1) Disconnect the electronic-controlled throttle valve connector B-12.
(2) Measure the resistance between electronic-controlled throttle valve side connector terminal No. 1 and No. 2.
Standard value: 0.3 - 80 Ω [at 20°C (68°F)]
Is the measured resistance between 0.3 and 80 Ω [at 20°C (68°F)]?
Go to Step 3.
Replace the throttle body assembly. Then go to Step 7.
 
STEP 3. Check harness connector B-26 at ECM for damage.
Is the harness connector in good condition?
Go to Step 4.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 7.
 
STEP 4. Check for harness damage between electronic-controlled throttle valve connector B-12 (terminal No. 1) and ECM connector B-26 (terminal No. 15).
Is the harness wire in good condition?
Go to Step 5.
Repair it. Then go to Step 7.
 
STEP 5. Check for harness damage between electronic-controlled throttle valve connector B-12 (terminal No. 2) and ECM connector B-26 (terminal No. 16).
Is the harness wire in good condition?
Go to Step 6.
Repair it. Then go to Step 7.
 
STEP 6. Using scan tool MB991958, read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P0638 set?
Replace the ECM (Refer to, Removal and Installation ). Then go to Step 7.
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
 
STEP 7. Using scan tool MB991958, read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P0638 set?
Retry the troubleshooting.
The inspection is complete.