C1252

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1252/52: Brake Booster Pump Motor on Time Abnormally Long

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

DTC C1253/53 - Pump Motor Relay Malfunction

DESCRIPTION

The skid control ECU detects decreases in the accumulator pressure according to the data from the accumulator pressure sensor, and then starts and stops the pump motor by operating the motor relay.
The skid control ECU usually drives the motor relay 1 for electronically controlled brake system control, and the motor relay 2 for ABS control. If either of them is malfunctioning, the other will substitute.






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: When replacing the skid control ECU or brake actuator assembly, perform initialization and calibration of the linear solenoid valve. Initialization

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Select the Active Test mode on the Techstream. Data List / Active Test

ABS / VSC / TRAC:





*: Electronically Controlled Brake System
(d) Check the operation sound of the ABS motor relay and motor when operating it with the Techstream.
OK:
The operation sound of the ABS motor relay and motor should be heard.
NG -- INSPECT ABS MTR FUSE
OK -- Continue to next step.
2. INSPECT BRAKE BOOSTER PUMP
(a) Turn the power switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(c) Disconnect the brake booster pump connectors.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE BRAKE BOOSTER PUMP
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE BOOSTER PUMP)
(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.





(b) Disconnect the skid control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)
(a) Reconnect the skid control ECU connector and the brake booster pump connectors.
(b) Connect the Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Select the Data List mode on the Techstream. Data List / Active Test

ABS / VSC / TRAC:





(e) Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on the Techstream with the motor stopped (not braking).
OK:
Accumulator pressure sensor voltage does not drop.
NG -- READ VALUE USING TECHSTREAM (PRESSURE SENSOR)
OK -- Continue to next step.
5. RECONFIRM DTC
(a) Turn the power switch off.
(b) Clear the DTCs.
(c) Turn the power switch on (IG).
(d) Check if the same DTC is recorded.
Result:






B -- REPLACE SKID CONTROL ECU
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
6. INSPECT ABS MTR FUSE
(a) Turn the power switch off.





(b) Remove the fusible link block from the engine room relay block.
(c) Check if the fusible link is melted.
OK:
The fusible link is not melted.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FUSIBLE LINK BLOCK (ABS MTR FUSE)
OK -- Continue to next step.
7. INSPECT ABS MOTOR RELAY (ABS MTR1, 2)





(a) Install the fusible link block to the engine room relay block with the bolt.
(b) Remove the ABS MTR1 relay and the ABS MTR2 relay.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE ABS MOTOR RELAY (ABS MTR1, 2)
OK -- Continue to next step.
8. INSPECT ENGINE ROOM NO. 2 RELAY BLOCK (POWER SOURCE TERMINAL)





(a) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK -- Continue to next step.
9. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER PUMP - ENGINE ROOM NO. 2 RELAY BLOCK)
(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.





(b) Disconnect the brake booster pump connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
10. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 2 RELAY BLOCK)
(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.





(b) Disconnect the skid control ECU connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE SKID CONTROL ECU
11. READ VALUE USING TECHSTREAM (PRESSURE SENSOR)
(a) Select the Data List mode on the Techstream. Data List / Active Test

ABS / VSC / TRAC:





(b) Select the Active Test mode on the Techstream. 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:





*: Electronically Controlled Brake System
(c) Perform the Active Test of the solenoid using the Techstream.





(d) 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.

NG -- REPLACE BRAKE ACTUATOR ASSEMBLY
OK -- REPLACE BRAKE BOOSTER PUMP