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)

• Not applicable
  

• Not applicable
  

DTC SET CONDITIONS

• Battery positive voltage is higher than 8.3 volts.
  

• The power line voltage of the electronic controlled throttle valve system should be 6.0 volts or less for 0.35 second.
  

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, or connector damage.
  
• ECM failed.
  

	Go to Step 2.

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

(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.

(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.

(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.

	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.

(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.

(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.

	Go to Step 9.

	Repair it. Then go to Step 14.

	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.

	Go to Step 11.

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

	Go to Step 12.

	Repair it. Then go to Step 14.

	Go to Step 13.

	Repair it. Then go to Step 14.

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 .

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.