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DTC P0657: Throttle Actuator Control Motor Relay Circuit Malfunction












CIRCUIT OPERATION




TECHNICAL DESCRIPTION




DESCRIPTIONS OF MONITOR METHODS




MONITOR EXECUTION




MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)


Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
Sensor (The sensor below is determined to be normal)

DTC SET CONDITIONS


Check Condition
Judgement Criterion

OBD-II DRIVE CYCLE PATTERN




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




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 A-18X at throttle actuator control motor relay for damage.


Q. 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 14.

STEP 2. Check the throttle actuator control motor relay.


(1)Remove the throttle actuator control motor relay.

(2)Check for continuity between the throttle actuator control motor relay terminal No. 1 and No. 2.

  • There should be continuity.

(3)Use jumper wires to connect throttle actuator control motor relay terminal No. 2 to the positive battery terminal and terminal No. 1 to the negative battery terminal.
(4)Check the continuity between the throttle actuator control motor relay terminal No. 3 and No. 4 while connecting and disconnecting the jumper wire at the negative battery terminal.

  • Continuity (2 Ω or less) <Negative battery terminal connected.>
  • Should be open loop. <Negative battery terminal disconnected.>
(5)Install the throttle actuator control motor relay.

Q. Is the measured resistance normal?

Go to Step 3.

Replace the throttle actuator control motor relay. Then go to Step 14.

STEP 3. Measure the power supply voltage at throttle actuator control motor relay harness side connector A-18X


(1)Disconnect the connector A-18X and measure at the harness side.

(2)Measure the voltage between terminal No. 4 and ground.

  • Voltage should be battery positive voltage.

Q. Is battery positive voltage (approximately 12 volts) present?

Go to Step 4.

Repair it harness wire between battery and throttle actuator control motor relay connector A-18X (terminal No. 4) because of open circuit or short circuit to ground. Then go to Step 14.

STEP 4. Measure the power supply voltage at throttle actuator control motor relay harness side connector A-18X.


(1)Disconnect the connector A-18X and measure at the harness side.
(2)Turn the ignition switch to the "ON" position.

(3)Measure the voltage between terminal No. 2 and ground.

  • Voltage should be battery positive voltage.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is battery positive voltage (approximately 12 volts) present?

Go to Step 6.

Go to Step 5.

STEP 5. Check harness connector A-30X at MFI relay for damage.


Q. Is the harness connector in good condition?

Repair harness wire between MFI relay connector A-30X (terminal No. 2) and throttle actuator control motor relay connector A-18X (terminal No. 2) because of open circuit or short circuit to ground. Then go to Step 14.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 14.

STEP 6. Measure the power supply voltage at ECM harness side connector B-109.


(1)Disconnect the connector B-109 and measure at the harness side.
(2)Short-circuit the terminal No. 73 of the ECM harness connector to the ground.

(3)Measure the voltage between terminal No. 84 and ground.

  • Voltage should be battery positive voltage.

Q. Is battery positive voltage (approximately 12 volts) present?

Go to Step 7.

Repair harness wire between throttle actuator control motor relay connector A-18X (terminal No. 1) and ECM connector B-109 (terminal No. 84) because of open circuit or short circuit to ground. Then go to Step 14.

STEP 7. Measure the power supply voltage at ECM harness side connector B-109.


(1)Disconnect the connector B-109 and measure at the harness side.
(2)Short-circuit the terminals No. 73 and No. 84 of the ECM harness connector to the ground.

(3)Measure the voltage between terminal No. 72 and ground.

  • Voltage should be battery positive voltage.

Q. Is battery positive voltage (approximately 12 volts) present?

Go to Step 10.

Go to Step 8.

STEP 8. Check for open circuit and short circuit to ground between throttle actuator control motor relay connector A-18X (terminal No. 3) and ECM connector B-109 (terminal No. 72).


Q. Is the harness wire in good condition?

Go to Step 9.
Repair it. Then go to Step 14.

STEP 9. Check for harness damage between MFI relay connector A-30X (terminal No. 2) and throttle actuator control motor relay connector A-18X (terminal No. 2).


Q. Is the harness wire in good condition?

Repair harness wire between throttle actuator control motor relay connector A-18X (terminal No. 1) and ECM connector B-109 (terminal No. 84) because of harness damage. Then go to Step 14.
Repair it. Then go to Step 14.

STEP 10. Check harness connector B-109 at ECM for damage.


Q. Is the harness connector in good condition?

Go to Step 11.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 14.

STEP 11. Check for harness damage between battery and throttle actuator control motor relay connector A-18X (terminal No. 4).


Q. Is the harness wire in good condition?

Go to Step 12.
Repair it. Then go to Step 14.

STEP 12. Check for harness damage between throttle actuator control motor relay connector A-18X (terminal No. 3) and ECM connector B-109 (terminal No. 72).


Q. Is the harness wire in good condition?

Go to Step 13.
Repair it. Then go to Step 14.

STEP 13. 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 P0657 set?

Replace the ECM. When the ECM is replaced, register the ID code. Refer to GROUP 42B, Diagnosis - ID Code Registration Judgment Table <Vehicles with KOS> or GROUP 42C, Diagnosis - ID Codes Registration Judgment Table <Vehicles with WCM> . Then go to Step 14.

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 14. 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 P0657 set?

Retry the troubleshooting.

The inspection is complete.