C1251

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1251/51: Open in Pump Motor Circuit

DTC C1251/51 - Open in Pump Motor Circuit

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.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTE: When replacing the master cylinder solenoid, perform zero point calibration Programming and Relearning.

HINT: Remove the hydraulic brake booster before the inspection Removal.

PROCEDURE

1. 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.

2. 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.

3. RECONFIRM DTC
(a) Reassemble the hydraulic brake booster assembly Reassembly.
(b) Install the hydraulic brake booster assembly Installation.
(c) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(d) Check if the same DTC is detected Reading and Clearing Diagnostic Trouble Codes.
Result:





B -- CHECK FOR INTERMITTENT PROBLEMS
A -- REPLACE MASTER CYLINDER SOLENOID