P0642

DTC P0642: Throttle Position Sensor Power Supply










TECHNICAL DESCRIPTION

- ECM checks the throttle position sensor power voltage for abnormal conditions.

DESCRIPTIONS OF MONITOR METHODS

Throttle position sensor source voltage is smaller 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 Condition

- Battery positive voltage is higher than 6.3 volts.
Judgement Criterion

- Throttle position sensor power voltage should be 4.1 volts or less for 0.3 second.

OBD-II DRIVE CYCLE PATTERN

None.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

- ECM failed.
- Short circuit in throttle position sensor power voltage to ground.

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. Measure the sensor supply voltage at throttle position sensor harness side connector B-11.

(1)Disconnect the connector B-11 and measure at the harness side.

(2)Turn the ignition switch to the "ON" position.





(3)Measure the voltage between terminal No. 5 and ground.

- Voltage should be between 4.9 and 5.1 volts.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage between 4.9 and 5.1 volts?

YES Go to Step 4.

NO Go to Step 2.

STEP 2. Check harness connector B-11 at the throttle position sensor and harness connector B-10 at the ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 3.
NO Repair it. Harness Connector Inspection.
Then go to Step 3.
STEP 3. Check for open circuit to ground or harness damage between the throttle position sensor connector B-11 and the ECM connector B-10.

(1)Disconnect the throttle position sensor connector B-11 and the ECM connector B-10.





(2)Measure the resistance between the throttle position sensor connector B-11 (terminal No. 5) and the ECM connector B-10 (terminal No. 12).

- Should be less than 2 ohms.





(3)Check for the continuity between the throttle position sensor connector B-11 (terminal No. 5) and ground.

- Not continuity.

Q. Is the harness wire in good condition?

YES Go to Step 4.

NO Repair it. Harness Connector Inspection.

STEP 4. 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 P0642 set?

YES Replace the ECM (Refer to, Removal and Installation Removal and Replacement).

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