Last Modified: 7-25-2017 6.8:8.0.
51 Doc ID: RM000000Y3L00EX
Model Year Start: 2007 Model: LS460 Prod Date Range: [09/2006 - ]
Title: BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1252/52,C1253/53; Brake
Booster Pump Motor on Time Abnormally Long; 2007 MY LS460 [09/2006 - ]
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 ABS motor relay (ABS MTR1) for electronically controlled brake
system control, and the ABS motor relay (ABS MTR2) for ABS control. If either is of them malfunctioning,
the other will substitute.
DTC INFORMATION DTC DETECTION CONDITION TROUBLE AREA
CODE CODE
• ABS motor relay
(ABS MTR1)
• ABS motor relay
C1252/52 130 Motor relay is on for at least 3 minutes.
(ABS MTR2)
• Brake
accumulator
• ABS motor relay
(ABS MTR1)
• Wire harness or
When the linear solenoid power supply 1 connector
(BS1) is 9.5 V or more, either of +BI1 or • Brake
C1253/53 134 +BI2 voltage is 7 V or more, and the motor accumulator
relay 1 is on, MTT input of less than 3.5 V pump motor
continues for 1 second or more. • Brake
accumulator
pump motor
circuit
↑ 138 When the linear solenoid power supply 2
• ABS motor relay
(BS2) is 9.5 V or more, either of +BI1 or
(ABS MTR2)
+BI2 voltage is 7 V or more, and the motor
• Wire harness or
relay 2 is on, MTT input of less than 3.5 V
connector
continues for 1 second or more.
DTC INFORMATION DTC DETECTION CONDITION TROUBLE AREA
CODE CODE
• Brake
accumulator
pump motor
• Brake
accumulator
pump motor
circuit
• ABS motor relay
(ABS MTR1)
• ABS motor relay
(ABS MTR2)
• Brake
MTT input is 3.5 V or more for at least 2
↑ 140 accumulator
seconds when motor relay 1 and 2 are off.
pump motor
• Brake
accumulator
pump motor
circuit
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. INSPECT FUSE (ABS MTR1, ABS MTR2, ABS MAIN1 AND ABS MAIN2)
(a) Remove the ABS MTR1, ABS MTR2, ABS MAIN1 and ABS MAIN2 fuses from the engine room
No. 2 relay block.
(b) Measure the resistance of the fuses.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
ABS MTR1 H-fuse Always Below 1 Ω
ABS MTR2 H-fuse Always Below 1 Ω
ABS MAIN1 Always Below 1 Ω
ABS MAIN2 Always Below 1 Ω
NG REPLACE FUSE
OK
PERFORM ACTIVE TEST USING INTELLIGENT TESTER OR TECHSTREAM (ABS
2.
RELAY)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Select the ACTIVE TEST mode on the intelligent tester or Techstream.
HINT:
• The ABS relay is a semiconductor relay. It does not emit operation sounds.
• The ABS relay cannot be removed and inspected, as it is part of the engine room No. 2 relay block.
(d) Remove the terminal cover.
(1) Intelligent tester
Skid control ECU
TESTER TEST PART CONTROL DIAGNOSTIC
DISPLAY RANGE NOTE
Turns Operation
Electronically
electronically sound of relay
Controlled
controlled ON / OFF (clicking sound)
Brake System
brake system and motor can
MTR RELAY
motor relay be heard
(2) Techstream
Skid control ECU
TESTER TEST PART CONTROL DIAGNOSTIC
DISPLAY RANGE NOTE
Turns Operation
Electronically
electronically sound of relay
Controlled
controlled ON / OFF (clicking sound)
Brake System
brake system and motor can
Motor Relay
motor relay be heard
(e) Measure the voltage according to the value(s) in the table below.
Standard voltage:
TESTER CONNECTION SWITCH CONDITION SPECIFIED CONDITION
Motor relay: ON 11 to 14 V
Terminal 23 or 24 - Body ground
Motor relay: OFF Below 1 V
Terminal 25 or 26 - Body ground Always 11 to 14 V
NG GO TO STEP 8
OK
3. CHECK HARNESS AND CONNECTOR (BRAKE ACCUMULATOR PUMP - ENGINE
ROOM NO. 2 RELAY BLOCK)
(a) Disconnect the A23 pump connector.
(b) Read value of intelligent tester or Techstream (ABS MTR relay).
(1) Connect the intelligent tester or Techstream to the DLC3.
(2) Turn the engine switch on (IG).
(3) Select the ACTIVE TEST mode on the intelligent tester or Techstream.
(1) Intelligent tester
Skid control ECU
TESTER DISPLAY TEST PART CONTROL DIAGNOSTIC NOTE
RANGE
Turns electronically Operation sound of relay
Electronically Controlled
controlled brake system ON / OFF (clicking sound) and motor can
Brake System MTR RELAY
motor relay be heard
(2) Techstream
Skid control ECU
TESTER DISPLAY TEST PART CONTROL DIAGNOSTIC NOTE
RANGE
Turns electronically Operation sound of relay
Electronically Controlled
controlled brake system ON / OFF (clicking sound) and motor can
Brake System Motor Relay
motor relay be heard
(c) Measure the voltage according to the value(s) in the
table below.
Standard voltage:
TESTER CONNECTION SWITCH SPECIFIED
CONDITION CONDITION
ABS MTR relay:
11 to 14 V
A23-2 (BM1) - Body ON
ground ABS MTR relay:
Below 1 V
OFF
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR
OK
4. READ VALUE USING INTELLIGENT TESTER (ABS MTR2 RELAY)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Select the ACTIVE TEST mode on the intelligent tester or Techstream.
(1) Intelligent tester
Skid control ECU
TESTER DISPLAY TEST PART CONTROL DIAGNOSTIC NOTE
RANGE
Electronically Controlled Turns electronically Operation sound of relay
Brake System MTR RELAY controlled brake system ON / OFF (clicking sound) and motor can
2 motor relay 2 be heard
(2) Techstream
Skid control ECU
TESTER DISPLAY TEST PART CONTROL DIAGNOSTIC NOTE
RANGE
Electronically Controlled Turns electronically Operation sound of relay
Brake System Motor Relay controlled brake system ON / OFF (clicking sound) and motor can
2 motor relay 2 be heard
(d) Check the operation sound of the ABS MTR2 relay and motor when operating it with the
intelligent tester or Techstream.
OK:
The operation sound of the ABS MTR relay 2 and motor are heard.
NG GO TO STEP 11
OK
5. INSPECT BRAKE ACCUMULATOR PUMP
(a) Turn the engine switch off.
(b) Disconnect the A23 and A24 pump connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
A2 (BM1) - A4 (GND1)
Always 10 Ω or less
B2 (BM2) - A4 (GND1)
A2 (BM1) - B2 (BM2)
Always Below 1 Ω
A4 (GND1) - B1 (GND2)
A2 (BM1) - A1 (MTT)
Always 950 to 1050 Ω
B2 (BM2) - A1 (MTT)
NG REPLACE BRAKE ACCUMULATOR PUMP
OK
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE
6.
ACCUMULATOR PUMP)
(a) Turn the engine switch off.
(b) Disconnect the A19 ECU connector.
(c) Disconnect the A23 pump connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
A19-37 (MTT) - A23-1 (MTT) Always Below 1 Ω
A19-37 (MTT) - Body ground Always 10 kΩ or higher
A23-4 (GND1) - Body ground Always Below 1 Ω
A24-1 (GND2) - Body ground Always Below 1 Ω
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR
OK
READ VALUE USING INTELLIGENT TESTER OR TECHSTREAM (ACCUMULATOR
7.
SENSOR)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Select the DATA LIST mode on the intelligent tester or Techstream.
(1) Intelligent tester
TESTER MEASUREMENT ITEM / NORMAL CONDITION DIAGNOSTIC
DISPLAY RANGE NOTE
ACC PRESS Accumulator pressure sensor / min.: 0 V, Specified value: 2.6 to
-
SENS max.: 5 V 3.8 V
(2) Techstream
TESTER DISPLAY MEASUREMENT ITEM / NORMAL CONDITION DIAGNOSTIC
RANGE NOTE
Accumulator Accumulator pressure sensor / min.: 0 Specified value: 2.6 to
-
Sensor V, max.: 5 V 3.8 V
(d) Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value
on the intelligent tester with the motor stopped (not braking) for 30 seconds.
OK:
The accumulator pressure sensor voltage change is within 0.2 V.
HINT:
• This inspection is performed to determine if there is a long term power malfunction when low
pressure is detected in the accumulator due to a sensor malfunction, fluid leak in the actuator, or
accumulator deterioration.
• If the reservoir fluid level drops, there may be a fluid leak.
NG GO TO STEP 16
OK
CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 JUNCTION BLOCK -
8.
BATTERY)
(a) Disconnect the 2F junction block connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
2F-1 - Body ground Always 11 to 14 V
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR
OK
INSPECT ENGINE ROOM NO. 2 RELAY BLOCK AND NO. 2 JUNCTION BLOCK
9.
(INNER CIRCUIT)
(a) Turn the engine switch off.
(b) Disconnect the 2B and 2F junction block connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
2F-1 - Terminal 25 or 26 Always Below 1 Ω
2B-1 - Terminal 23 or 24 Always Below 1 Ω
REPLACE ENGINE ROOM NO. 2 RELAY
NG BLOCK AND NO. 2 JUNCTION BLOCK
OK
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 2
10.
JUNCTION BLOCK)
(a) Turn the engine switch off.
(b) Disconnect the A19 ECU connector.
(c) Disconnect the 2G junction block connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
A19-35 (MR1) - 2G-14 Always Below 1 Ω
A19-36 (R1-) - 2G-13 Always Below 1 Ω
A19-35 (MR1) - Body ground Always 10 kΩ or higher
A19-36 (R1-) - Body ground Always 10 kΩ or higher
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR
REPLACE ENGINE ROOM NO. 2 JUNCTION
OK BLOCK
11. INSPECT ABS MOTOR RELAY (ABS MTR2)
(a) Remove the ABS motor relay.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONDITION SPECIFIED
CONNECTION CONDITION
When battery voltage is not applied to terminals 1 and
3-5 10 kΩ or higher
2
3-5 When battery voltage is applied to terminals 1 and 2 Below 1 Ω
NG REPLACE ABS MOTOR RELAY (ABS MTR2)
OK
12. CHECK HARNESS AND CONNECTOR (NO. 3 RELAY BLOCK - BATTERY)
(a) Remove the ABS motor relay (ABS MTR2).
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
ABS motor relay terminal 5 (ABS MTR2) - Body ground Always 11 to 14 V
NG
REPAIR OR
REPLACE
HARNESS
OR
CONNECTOR
OK
CHECK HARNESS AND CONNECTOR (BRAKE ACCUMULATOR PUMP - NO. 3 RELAY
13.
BLOCK)
(a) Disconnect the A24 pump connector.
(b) Remove the ABS motor relay (ABS MTR2)..
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
A24-2 (BM2) - ABS motor relay terminal 3 (ABS MTR2) Always Below 1 Ω
A24-2 (BM2) - Body ground Always 10 kΩ or higher
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR
OK
14. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - NO. 3 RELAY BLOCK)
(a) Disconnect the A21 ECU connector.
(b) Remove the ABS motor relay (ABS MTR2).
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
A21-36 (MR2) - ABS motor relay terminal 1 (ABS MTR2) Always Below 1 Ω
A21-37 (R2-) - ABS motor relay terminal 2 (ABS MTR2) Always Below 1 Ω
A21-37 (R2-) - Body ground Always 10 kΩ or higher
A21-36 (MR2) - Body ground Always 10 kΩ or higher
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR
OK
15. RECONFIRM DTC
(a) Clear the DTC .
(b) Turn the engine switch on (IG).
(c) Check if the same DTCs are recorded .
HINT:
Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before
rechecking for DTCs.
Result
RESULT PROCEED TO
DTCs (C1252/52 and C1253/53) are not output A
DTCs (C1252/52 and C1253/53) are output B
B REPLACE SKID CONTROL ECU
A END
PERFORM ACTIVE TEST USING INTELLIGENT TESTER OR TECHSTREAM (SMC1,
16.
SMC2, SLRRR, AND SLRRL)
(a) Connect the intelligent tester or Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the intelligent tester or Techstream main switch on.
(d) Select the ACTIVE TEST mode on the intelligent tester or Techstream.
HINT:
The ACTIVE TEST can be performed when the following conditions are met.
• Main relay 1 and 2 are on.
• Shift lever is P position.
• Parking brake is on.
• Vehicle speed is 0 km/h (0 mph).
(1) Intelligent tester
Skid Control ECU:
TESTER TEST PART CONTROL DIAGNOSTIC NOTE
DISPLAY RANGE
Turns electronically controlled brake Operation sound of solenoid
SMC1 ON / OFF
system solenoid (SMC1) (clicking sound) can be heard
Turns electronically controlled brake Operation sound of solenoid
SMC2 ON / OFF
system solenoid (SMC2) (clicking sound) can be heard
SLRRR Operation sound of solenoid
Turns SLRRR solenoid ON / OFF
CLOSE (clicking sound) can be heard
SLRRL Operation sound of solenoid
Turns SLRRL solenoid ON / OFF
CLOSE (clicking sound) can be heard
(2) Techstream
Skid Control ECU:
TESTER DISPLAY TEST PART CONTROL DIAGNOSTIC NOTE
RANGE
Turns electronically Operation sound of
Electronically Controlled Brake
controlled brake system ON / OFF solenoid (clicking sound)
System Solenoid (SMC1)
solenoid (SMC1) can be heard
Turns electronically Operation sound of
Electronically Controlled Brake
controlled brake system ON / OFF solenoid (clicking sound)
System Solenoid (SMC2)
solenoid (SMC2) can be heard
Electronically Controlled Brake Operation sound of
System Solenoid (SLRRR) Turns SLRRR solenoid ON / OFF solenoid (clicking sound)
Valve Close can be heard
Electronically Controlled Brake Operation sound of
System Solenoid (SLRRL) Turns SLRRR solenoid ON / OFF solenoid (clicking sound)
Valve Close can be heard
(e) Using the intelligent tester or Techstream, turn SMC1, SMC2, SLRRR, or SLRRL ON.
(f) Check that each wheel cylinder's output value does not increase.
OK:
Each wheel cylinder's output value does not increase.
HINT:
If any of wheel cylinder's output value increases, there may be a brake fluid leak in the brake
actuator.
NG REPLACE BRAKE ACTUATOR
OK REPLACE BRAKE ACCUMULATOR PUMP
