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.





HINT: The pump motor continues operation for the first 3 minutes, and then starts and stops repeatedly.

WIRING DIAGRAM





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 area indicated by C1253/53, C1254/54, or C1256/56 first.

PROCEDURE

1. CHECK 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 pump motor operates.
Result:





D -- RECONFIRM DTC
C -- READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)
B -- REPLACE MASTER CYLINDER SOLENOID AND BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
A -- Continue to next step.

2. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS (MT+ / MT-)
(a) Using a screwdriver, remove the 2 plugs from the hydraulic brake booster assembly Removal.
(b) Check the tightening torque of the 2 screws which tighten the wire harness connecting the hydraulic brake booster assembly and the brake booster pump motor Removal.
OK:
The harness is tightened to the specified 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 (MT+ / MT-)




(a) Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly Removal.
(b) Measure the resistance between the red wire (MT+) and the black wire (MT-).
Standard resistance:
2 Ohms

NG -- REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
OK -- Continue to next step.

4. READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to ON and turn the Techstream main switch ON.
(c) Select "Data List" mode on Techstream.

ABS/VSC/TRAC





(d) Check the accumulator output value.
Result:





C -- REPLACE MASTER CYLINDER SOLENOID AND BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
B -- REPLACE HYDRAULIC BRAKE BOOSTER
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 detected 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 MASTER CYLINDER SOLENOID AND BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY