DTC C1391/69: Accumulator Leak Malfunction: Procedure

1. Check that there is no fluid leakage in the brake line between the brake actuator and the wheel cylinder which is indicated by DTCs.
   Fig 1: Identifying Brake Fluid Level

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check that the brake is not dragging.

   OK

   There is no fluid leakage or dragging.

NG → REPAIR OR REPLACE APPLICABLE PART 

OK: Go to next step 

1. Clear the DTCs, refer to DTC CHECK / CLEAR .
2. Turn the ignition switch to ON (READY).
3. Check if the same DTC is recorded, refer to DTC CHECK / CLEAR .

   Result

   Result	Proceed to
   DTC (C1391/69) is output	A
   DTC (C1391/69) is not output	B

B → See step   5 

A: Go to next step 

1. Turn the ignition switch off.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to ON.
4. Select the Active Test on the Techstream, refer to DATA LIST / ACTIVE TEST .

   HINT: 

   The Active Test can be performed when the following conditions are met.

   • ABS main relays 1 and 2 are on.
   • Shift lever is in P.
   • Parking brake is applied.
   • Vehicle speed is 0 km/h (0 mph).
   ABS/VSC/TRAC
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   ECB* Solenoid (SMC1)	Master cut solenoid (SMC1)	Solenoid ON/OFF	Operation sound of solenoid (clicking sound) can be heard
   ECB* Solenoid (SMC2)	Master cut solenoid (SMC2)	Solenoid ON/OFF	Operation sound of solenoid (clicking sound) can be heard
   ECB* Solenoid (SLRRL) Value Close	Linear solenoid (RLR) valve	Valve close ON/OFF	-
   ECB* Solenoid (SLRRR) Value Close	Linear solenoid (RRR) valve	Valve close ON/OFF	-

   *: Electronically Controlled Brake System

5. Perform the Active Test of the solenoid using the Techstream.
   Fig 2: Identifying Brake Actuator Inner Diagram

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Select the Data List on the Techstream, refer to DATA LIST / ACTIVE TEST .
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   FR W/C Sensor	FR wheel cylinder pressure sensor / Min.: 0.00 V, Max.: 5.00 V	When brake pedal is released: 0.3 to 0.7 V	Reading increases when brake pedal is depressed
   FL W/C Sensor	FL wheel cylinder pressure sensor / Min.: 0.00 V, Max.: 5.00 V	When brake pedal is released: 0.3 to 0.7 V	Reading increases when brake pedal is depressed
   RR W/C Sensor	RR wheel cylinder pressure sensor / Min.: 0.00 V, Max.: 5.00 V	When brake pedal is released: 0.3 to 0.7 V	Reading increases when brake pedal is depressed
   RL W/C Sensor	RL wheel cylinder pressure sensor / Min.: 0.00 V, Max.: 5.00 V	When brake pedal is released: 0.3 to 0.7 V	Reading increases when brake pedal is depressed

7. Check that the output value of each wheel cylinder does not increase.

   OK

   The output value of each wheel cylinder does not increase.

   HINT: 

   If any output value increases, there may be a brake fluid leak in the brake actuator.

   Result

   Result	Proceed to
   The output value of any wheel cylinder increases	A
   The output values of all wheel cylinders do not increase	B

B → See step   6 

A → See step   4