P0638

DTC P0638: Throttle Actuator Control Motor Circuit Range/Performance

THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE PROBLEM CIRCUIT

- Refer to DTC P2101 - Throttle Actuator Control Motor Magneto Malfunction P2101 .

CIRCUIT OPERATION

- Refer to DTC P2101 - Throttle Actuator Control Motor Magneto Malfunction P2101 .

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 stored 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 higher 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 0.04 volt or more.
Judgement Criterion

- Throttle position sensor (main) output voltage has continued to be higher than the target throttle position sensor (main) voltage by 0.5 volt or more for 0.4 second.
Check Conditions

- Battery positive voltage is higher 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 1.5 volts or lower.
Judgement Criterion

- Difference between throttle position sensor (main) output voltage and target throttle position sensor (main) voltage is 0.6 volt or higher for 0.4 second.
Check Conditions

- Battery positive voltage is higher than 8.3 volts.
- Throttle position sensor (main) output voltage is between 0.2 and 4.8 volts.
Judgement Criterion

- Difference between throttle position sensor (main) output voltage and target throttle position sensor (main) voltage is 1 volt or higher for 0.4 second.
Check Condition

- Battery positive voltage is higher than 8.3 volts.
Judgement Criterion

- Throttle position sensor (main) default opening learn value is 4 volts or higher.

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 Tools:

- 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-11 at throttle actuator control motor for damage.

Q. Is the harness connector in good condition?

YES Go to Step 2.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 7..
STEP 2. Check the throttle actuator control motor.

(1)Disconnect the connector B-11.

(2)Measure the resistance between throttle actuator control motor side connector terminal No. 1 and No. 2.
Standard value: 0.3 - 80ohms [at 20°C (68°F)]

Q. Is the measured resistance between 0.3 and 80ohms [at 20°C (68°F)]?

YES Go to Step 3.

NO Replace the throttle body assembly. Then go to Step 7.

STEP 3. Check harness connector B-09 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 4.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 7.
STEP 4. Check for harness damage between throttle actuator control motor connector B-11 (terminal No. 1) and ECM connector B-09 (terminal No. 15).

Q. Is the harness wire in good condition?

YES Go to Step 5.
NO Repair it. Then go to Step 7.
STEP 5. Check for harness damage between throttle actuator control motor connector B-11 (terminal No. 2) and ECM connector B-09 (terminal No. 16).

Q. Is the harness wire in good condition?

YES Go to Step 6.
NO Repair it. Then go to Step 7.
STEP 6. Using scan tool MB991958, read the diagnostic trouble code
(DTC).

CAUTION:
To 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.

Q. Is DTC P0638 set?

YES Replace the ECM (Refer to, Removal and Installation Removal and Replacement).
Then go to Step 7.

NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

STEP 7. Using scan tool MB991958, read the diagnostic trouble code
(DTC).