VEHICLE STABILITY CONTROL SYSTEM (for Vacuum Brake Booster), Diagnostic DTC:C1407, C1408

DESCRIPTION

Refer to DTCs C1401 and C1402 Click here.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

   
   

   1. Using the intelligent tester, check for any momentary interruption in the wire harness and connector corresponding to the DTC Click here.

      ABS/VSC/TRC

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      RR Speed Open	Rear speed sensor RH open circuit detection/ Error or Normal	Normal	-
      RL Speed Open	Rear speed sensor LH open circuit detection/ Error or Normal	Normal	-

      OK
      Normal (there are no momentary interruptions).

      Tech Tips

      Perform the above inspection before removing the sensor and disconnecting the connector.

   
   

   NG

   INSPECT SKID CONTROL SENSOR WIRE Click here

   OK

2. READ VALUE USING INTELLIGENT TESTER (RR/RL WHEEL SPEED)

   
   

   1. Turn the ignition switch off

   2. Connect the intelligent tester to the DLC3.

   3. Start the engine.

   4. Turn the intelligent tester on.

   5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

      ABS/VSC/TRC

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      RR Wheel Speed	Rear speed sensor RH value/ min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)	Actual wheel speed	No large fluctuations when driving at a constant speed.
      RL Wheel Speed	Rear speed sensor LH value/ min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)	Actual wheel speed	No large fluctuations when driving at a constant speed.

   6. Check the speed value output from the speed sensor displayed on the intelligent tester.

      Tech Tips

      Factors that affect the indicated vehicle speed include tire size, tire inflation and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, refer to the reference chart Click here.

      OK
      The speed value output from the speed sensor displayed on the intelligent tester is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).

   
   

   NG

   INSPECT SKID CONTROL SENSOR WIRE Click here

   OK

3. RECONFIRM DTC

   
   

   1. Turn the ignition switch off.

   2. Clear the DTCs Click here.

   3. Start the engine.

   4. Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.

   5. Check if the same DTC is output Click here.

      Result

      Result	Proceed to
      DTC is not output	A
      DTC is output	B

   
   

   B

   REPLACE BRAKE ACTUATOR ASSEMBLY Click here

   A

   USE SIMULATION METHOD TO CHECK Click here

4. INSPECT SKID CONTROL SENSOR WIRE

   

   Text in Illustration

   *A	for RH	*B	for LH
   *1	Skid Control Sensor Wire	-	-

   
   

   1. Make sure that there is no looseness at the locking parts and connecting parts of the connectors.

   2. Remove the skid control sensor wire Click here.

   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for RH Tester Connection Condition Specified Condition Sq1-4 - q1-2 (RR+) Always Below 1 Ω Sq1-3 - q1-1 (RR-) Always Below 1 Ω Sq1-4 - Sq1-3 Always 10 kΩ or higher Sq1-4 - Sq1-1 Always 10 kΩ or higher Sq1-4 - Sq1-2 Always 10 kΩ or higher
      for LH Tester Connection Condition Specified Condition Sq1-2 - q2-2 (RL+) Always Below 1 Ω Sq1-1 - q2-1 (RL-) Always Below 1 Ω Sq1-2 - Sq1-1 Always 10 kΩ or higher Sq1-2 - Sq1-3 Always 10 kΩ or higher Sq1-2 - Sq1-4 Always 10 kΩ or higher

   
   

   NG

   REPLACE SKID CONTROL SENSOR WIRE Click here

   OK

5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - REAR SPEED SENSOR)

   
   

   1. Install the skid control sensor wire.

   2. Disconnect the A6 skid control ECU connector.

   3. Disconnect the q1 and/or q2 speed sensor connector.

   4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for RH Tester Connection Condition Specified Condition A6-17 (RR+) - q1-2 (RR+) Always Below 1 Ω A6-17 (RR+) - Body ground Always 10 kΩ or higher A6-16 (RR-) - q1-1 (RR-) Always Below 1 Ω A6-16 (RR-) - Body ground Always 10 kΩ or higher
      for LH Tester Connection Condition Specified Condition A6-5 (RL+) - q2-2 (RL+) Always Below 1 Ω A6-5 (RL+) - Body ground Always 10 kΩ or higher A6-4 (RL-) - q2-1 (RL-) Always Below 1 Ω A6-4 (RL-) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. CHECK TERMINAL VOLTAGE (RR+, RL+)

   
   

   1. Connect the A6 skid control ECU connector.

   2. Disconnect the q1 and/or q2 speed sensor connector.

   3. 

      Text in Illustration

      *A	for RH
      *B	for LH
      *a	Front view of wire harness connector (to Rear Speed Sensor)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      for RH Tester Connection Switch Condition Specified Condition q1-2 (RR+) - Body ground Ignition switch ON 8 to 14 V
      for LH Tester Connection Switch Condition Specified Condition q2-2 (RL+) - Body ground Ignition switch ON 8 to 14 V

   
   

   NG

   REPLACE BRAKE ACTUATOR ASSEMBLY Click here

   OK

   REPLACE REAR SPEED SENSOR Click here