C1252

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1252/52: Brake Booster Pump Motor on Time Abnormally Long

DTC C1252/52 - Brake Booster Pump Motor on Time Abnormally Long

DESCRIPTION

The motor relay (semiconductor relay) is built into the master cylinder solenoid and drives the pump motor based on a signal from the skid control ECU.





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT: When C1253/53, C1254/54 or C1256/56 is output together with C1252/52, inspect and repair the trouble areas indicated by C1253/53, C1254/54 or C1256/56 first.

PROCEDURE

1. CHECK HYDRAULIC BRAKE BOOSTER PUMP MOTOR OPERATION
(a) Turn the ignition switch to OFF.
(b) Depress the brake pedal more than 20 times.
(c) Turn the ignition switch to the ON position.
(d) Check how the hydraulic brake booster pump motor operates.





D -- RECONFIRM DTC
C -- READ VALUE USING DATA LIST (ACCUMULATOR PRESSURE SENSOR)
B -- REPLACE HYDRAULIC BRAKE BOOSTER
A -- Continue to next step.
2. CHECK BRAKE PUMP MOTOR WIRE HARNESS CONNECTION (MT+ / MT-)
(a) Using a screwdriver, remove the 2 plugs from the hydraulic brake booster (Service and Repair).
(b) Check the tightening torque of 2 screws which fasten the wire harness connecting hydraulic brake booster and brake booster pump (Service and Repair).
Torque: 2.9 Nm (30 kgf-cm, 26 in-lbf)
NG -- RETIGHTEN SCREWS
OK -- Continue to next step.
3. CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS (MT+/MT-)





(a) Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly.
(b) Measure the resistance between the red wire (MT+) and black wire (MT-).
Resistance:
2 Ohms
NG -- REPLACE HYDRAULIC BRAKE BOOSTER
OK -- Continue to next step.
4. READ VALUE USING DATA LIST (ACCUMULATOR PRESSURE SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn Techstream ON.
(d) Select the Data List mode on Techstream.

ABS/VSC/TRAC





(e) Check that the accumulator pressure sensor output is normal.





C -- REPLACE HYDRAULIC BRAKE BOOSTER
B -- REPLACE MASTER CYLINDER SOLENOID
A -- Continue to next step.
5. RECONFIRM DTC
(a) Clear the DTCs (Reading and Clearing Diagnostic Trouble Codes).
(b) Turn the ignition switch to OFF.
(c) Turn the ignition switch to the ON position.
(d) Wait for more than 5 minutes.
(e) Check if the same DTCs are recorded.





B -- REPLACE HYDRAULIC BRAKE BOOSTER
A -- REPLACE MASTER CYLINDER SOLENOID