DTC C1251/51 Open in Pump Motor Circuit: Wiring Diagram

WARNING: This page is about a different car, the 2006 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Wiring Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NOTE: When replacing the skid control ECU, perform zero point calibration (See CALIBRATION ).

HINT:

When C0273/13, C0274/14 or C1361/91 is output together with C1251/51, inspect and repair the trouble areas indicated by C0273/13, C0274/14 or C1361/91 first.

PERFORM ACTIVE TEST BY INTELLIGENT TESTER (ABS MOTOR RELAY)

Connect the intelligent tester to the DLC3.
Start the engine.
Select the Active Test mode on the intelligent tester.

Check the operating sound of the ABS motor relay and motor when operating it with the intelligent tester.

ABS / VSC:

DIAGNOSIS CHART

Item (Display)	Vehicle Condition / Test Details	Diagnostic Note
MOTOR RELAY	Turns ABS motor relay ON / OFF	Operating sound of relay (clicking sound) and motor can be heard

OK: The operating sound of the ABS motor relay and motor can be heard.

OK : Go to step 3

NG : GO TO NEXT STEP

INSPECT BRAKE ACTUATOR ASSEMBLY (GND TERMINAL)

Turn the engine switch off.
Disconnect the brake actuator connector.

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

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
A13-1 (GND2) - Body ground	Always	Below 1 Ω

Fig 2: Inspecting Brake Actuator Assembly (Gnd Terminal)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

OK : GO TO NEXT STEP

RECONFIRM DTC

Reconnect the brake actuator connector.
Clear the DTC (See DTC CHECK / CLEAR ).
Start the engine.
Drive the vehicle at the speed of 4.3 mph (7 km/h) or more.

Check if the same DTC is recorded (See DTC CHECK / CLEAR ).

Result

CONDITION CHART

Condition	Proceed to
DTC (C1251/51) is not output	A
DTC (C1251/51) is output	B

HINT:

If a speed signal of 4 mph (6 km/h) or more is input to the skid control ECU, with the engine switch on (IG) and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.
If a normal system code is output (trouble code is not output), slightly jiggle the connectors, wire harness, and fuses of the brake actuator assembly. Make sure that no DTCs are output.
If any DTCs are output while jiggling a connector or wire harness of the brake actuator assembly, inspect and repair the connector or wire harness.

B : REPLACE SKID CONTROL ECU

A : USE SIMULATION METHOD TO CHECK