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DTC P0657: Throttle Actuator Control Motor Relay Circuit Malfunction

 
 
 
 
CIRCUIT OPERATION
  • Battery positive voltage is applied to the throttle actuator control motor relay terminal (terminal No. 4).
  • Battery positive voltage is applied to the throttle actuator control motor relay terminal (terminal No. 2) from the MFI relay (terminal No. 2).
  • ECM (terminal No. 84) applies current to the throttle actuator control motor relay coil by turning ON the power transistor in the unit in order to turn the relay ON.
  • When the throttle actuator control motor relay turns ON, battery positive voltage is supplied by the throttle actuator control motor relay (terminal No. 3) to the ECM (terminal No. 72).
 
 
TECHNICAL DESCRIPTION
  • When the ignition switch ON signal is input into the ECM, the ECM turns ON the throttle actuator control motor relay.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Throttle actuator control motor relay circuit 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 more than 8.3 volts.
Judgment Criterion
  • The power line voltage of the electronic-controlled throttle valve system is less than 6.0 volts for 0.35 second.
 
 
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 actuator control motor relay failed.
  • Open or shorted throttle actuator control motor relay circuit, harness damage 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 A-25X at throttle actuator control motor relay 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 15.
 
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 for 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 ohms or less). <Negative battery terminal connected>
  • Should be open loop. <Negative battery terminal disconnected>
(5) Install the throttle actuator control motor relay.
Is the measured resistance normal?
Go to Step 3.
Replace the throttle actuator control motor relay. Then go to Step 15.
 
STEP 3. Measure the power supply voltage at throttle actuator control motor relay harness side connector A-25X.
(1) Disconnect the connector A-25X and measure at the harness side.
(2) Measure the voltage between terminal No. 4 and ground.
  • Voltage should be battery positive voltage.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 4.
Repair harness wire between battery and throttle actuator control motor relay connector A-25X (terminal No. 4) because of open circuit or short circuit to ground. Then go to Step 15.
 
STEP 4. Measure the power supply voltage at throttle actuator control motor relay harness side connector A-25X.
(1) Disconnect the connector A-25X 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.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check harness connector A-37X at MFI relay for damage.
Is the harness connector in good condition?
Repair harness wire between MFI relay connector A-37X (terminal No. 2) and throttle actuator control motor relay connector A-25X (terminal No. 2) because of open circuit or short circuit to ground. Then go to Step 15.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 15.
 
STEP 6. Check harness connector B-27 at ECM for damage.
Is the harness connector in good condition?
Go to Step 7.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 15.
 
STEP 7. Measure the power supply voltage at ECM harness side connector B-27.
(1) Disconnect the connector B-27 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.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 8.
Repair harness wire between throttle actuator control motor relay connector A-25X (terminal No. 1) and ECM connector B-27 (terminal No. 84) because of open circuit or short circuit to ground. Then go to Step 15.
 
STEP 8. Measure the power supply voltage at ECM harness side connector B-27.
(1) Disconnect the connector B-27 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.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 12.
Go to Step 9.
 
STEP 9. Check for open circuit and short circuit to ground between throttle actuator control motor relay connector A-25X (terminal No. 3) and ECM connector B-27 (terminal No. 72).
Is the harness wire in good condition?
Go to Step 10.
Repair it. Then go to Step 15.
 
STEP 10. Check harness connector A-37X at MFI relay for damage.
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 15.
 
STEP 11. Check for harness damage between MFI relay connector A-37X (terminal No. 2) and throttle actuator control motor relay connector A-25X (terminal No. 2).
Is the harness wire in good condition?
Repair harness wire between throttle actuator control motor relay connector A-25X (terminal No. 1) and ECM connector B-27 (terminal No. 84) because of harness damage. Then go to Step 15.
Repair it. Then go to Step 15.
 
STEP 12. Check for harness damage between battery and throttle actuator control motor relay connector A-25X (terminal No. 4).
Is the harness wire in good condition?
Go to Step 13.
Repair it. Then go to Step 15.
 
STEP 13. Check for harness damage between throttle actuator control motor relay connector A-25X (terminal No. 3) and ECM connector B-27 (terminal No. 72).
Is the harness wire in good condition?
Go to Step 14.
Repair it. Then go to Step 15.
 
STEP 14. 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 P0657 set?
Replace the ECM (Refer to, Removal and Installation ). Then go to Step 15.
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 15. 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 P0657 set?
Retry the troubleshooting.
The inspection is complete.