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

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: 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.





HINT: The pump motor continues operation for the first 3 minutes, then repeats start and stop.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: When replacing the hydraulic brake booster assembly (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 area indicated by C1253/53, C1254/54, or C1256/56 first.

PROCEDURE

1. CHECK PUMP MOTOR OPERATION
(a) Turn the engine switch off.
(b) Depress the brake pedal more than 20 times.
(c) Turn the engine switch on (IG).
(d) Check how the pump motor operates.

Result





D -- RECONFIRM DTC
C -- READ VALUE USING TECHSTREAM (ACCUMULATOR SENSOR)
B -- REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
A -- Continue to next step.
2. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS
(a) Remove the hydraulic brake booster assembly.
(b) Using a screwdriver, remove the 2 plugs from the hydraulic brake booster assembly.
(c) Check the tightening torque of the 2 screws which tighten the wire harness connecting the hydraulic brake booster assembly and brake booster pump.
OK:
The harness is tightened to the specific torque.
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





(a) Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
OK -- Continue to next step.
4. READ VALUE USING TECHSTREAM (ACCUMULATOR SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

ABS/VSC/TRAC





(d) Check the accumulator output value.

Result





C -- REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY
B -- REPLACE MASTER CYLINDER SOLENOID
A -- Continue to next step.
5. RECONFIRM DTC
(a) Clear the DTC. Reading and Clearing Diagnostic Trouble Codes
(b) Turn the engine switch off.
(c) Turn the engine switch on (IG).
(d) Wait for more than 5 minutes.
(e) Check if the same DTC is output. Reading and Clearing Diagnostic Trouble Codes
HINT: Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result





B -- REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
A -- REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY