C1253

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1253/53: Pump Motor Relay Malfunction



DESCRIPTION

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






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE:
When replacing the hydraulic brake booster (master cylinder solenoid), perform zero point calibration Calibration.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (H/B MOTOR RELAY)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position and push Techstream main switch ON.
(c) Start the engine.
(d) Select "Active Test" mode on Techstream.

ABS/VSC/TRAC





(e) Check operation sound of the H/B motor individually when operating it with Techstream.
OK:
The operation sound of the H/B motor can be heard.
OK -- RECONFIRM DTC
NG -- Continue to next step.
2. INSPECT SKID CONTROL ECU (+BM TERMINAL)




(a) Disconnect the skid control ECU connectors.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (+BM CIRCUIT)
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (GND TERMINAL)




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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
4. RECONFIRM DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Turn the ignition switch off.
(c) Depress the brake pedal more than 20 times.
(d) Turn the ignition switch to the ON position.
(e) Wait until the pump motor stops.
(f) Depress the brake pedal several times until the pump motor turns on.
(g) Wait until the pump stops.
(h) Repeat (f) and (g) 3 more times.
(i) 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 -- END
A -- REPLACE HYDRAULIC BRAKE BOOSTER