Brake Booster Pump Motor on Time Abnormally Long - Vehicle Stability Control System

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.






INSPECTION PROCEDURE
NOTE: When replacing the master cylinder solenoid, perform zero point calibration Programming and Relearning.
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 off.
(b) Depress the brake pedal more than 20 times.
(c) Turn the ignition switch to ON.
(d) Check how the hydraulic brake booster pump motor operates.
Result:






D -- RECONFIRM DTC
C -- READ VALUE USING DATA LIST (ACCUMULATOR PRESSURE SENSOR)
B -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
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 Disassembly.
(b) Check the tightening torque of 2 screws which fasten the wire harness connecting the hydraulic brake booster and brake booster pump Reassembly.
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-).
Standard resistance:
Below 2 Ohms
NG -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
OK -- Continue to next step.
4. READ VALUE USING DATA LIST (ACCUMULATOR PRESSURE SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the tester to ON.
(d) Select the following menu items: Chassis / ABS/VSC/TRAC/ Data List

DATA LIST: ABS/VSC/TRAC





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






C -- REPLACE HYDRAULIC BRAKE BOOSTER
B -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
A -- Continue to next step.
5. RECONFIRM DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Turn the ignition switch off.
(c) Turn the ignition switch to ON.
(d) Wait for more than 5 minutes.
(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
Result:






B -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
A -- REPLACE MASTER CYLINDER SOLENOID