Lexus ES: Malfunction in Motor (C1427)
DESCRIPTION
When the power switch is on (READY), the stop light switch assembly off and the vehicle speed is 20 km/h (12 mph) or more, the skid control ECU (brake booster with master cylinder assembly) performs a self-diagnosis of the ABS motor relay circuit during the initial check of the actuator.
| DTC No. | Detection Item | INF Code | DTC Detection Condition | Trouble Area | MIL | Note |
|---|---|---|---|---|---|---|
| C1427 | Malfunction in Motor | 1159 | The pump motor built into the brake actuator assembly is not operating correctly. |
| Comes on |
|
MONITOR DESCRIPTION
The skid control ECU (brake booster with master cylinder assembly) monitors the voltage of the ABS motor. When the ABS motor is normal and the ABS motor relay is turned off, the voltage of the ABS motor drops gradually due to rotational inertia; however, if the ABS motor is not turning and the ABS motor relay is turned off, the voltage of the ABS motor drops immediately. If the voltage of the ABS motor drops considerably quickly when the ABS motor relay is turned off, the skid control ECU (brake booster with master cylinder assembly) judges that the ABS motor is not operating and illuminates the MIL and stores this DTC.
MONITOR STRATEGY
| Related DTCs | C1427: ABS pump motor stuck |
| Required Sensors/Components(Main) | Brake actuator assembly |
| Required Sensors/Components(Related) | Skid control ECU (brake booster with master cylinder assembly) Brake actuator assembly |
| Frequency of Operation | Continuous |
| Duration | 2 times |
| MIL Operation | Immediately |
| Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
| Monitor runs whenever the following DTCs are not stored | None |
| Both of the following conditions are met | - |
| Skid control ECU (brake booster with master cylinder assembly) state | Initial check |
| After command to ABS motor relay on to off detection, 0.002 seconds passes | Met |
TYPICAL MALFUNCTION THRESHOLDS
| ABS pump motor voltage | Less than 1.3 V for 0.022 seconds or more within 0.024 seconds |
COMPONENT OPERATING RANGE
| All of the following conditions are met | - |
| Skid control ECU (brake booster with master cylinder assembly) state | Initial check |
| After command to ABS motor relay on to off detection, 0.002 seconds passes | Met |
| ABS pump motor voltage | Less than 1.3 V for less than 0.022 seconds within 0.024 seconds |
CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG).
- Turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the power switch off.
- Turn the power switch on (READY).
- Turn the Techstream on.
- Drive the vehicle at a speed of 20 km/h (12 mph) or more for 1 minute.
- Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
-
Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
-
If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here
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HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
-
After replacing the skid control ECU (brake booster with master cylinder assembly) or brake actuator assembly, perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".
Click here
- Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY) |
(a) Select the Active Test on the Techstream.
Click here
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Motor Relay | ABS motor relay | Relay ON/OFF | Operating sound of motor can be heard. |
| Tester Display |
|---|
| Motor Relay |
(b) Check the operating sound of the ABS motor relay when operating it with the Techstream.
| Result | Proceed to |
|---|---|
| The operating sound is heard. | A |
| The operating sound is not heard. | B |
| B | .gif) | GO TO STEP 3 |
|
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| 2. | RECONFIRM DTC |
(a) Clear the DTCs.
Click here
(b) Turn the power switch off.
(c) Turn the power switch on (READY).
(d) Perform a road test.
(e) Check if the same DTC is output.
Click here
| Result | Proceed to |
|---|---|
| DTC C1427 is not output. | A |
| DTC C1427 is output. | B |
| A | | USE SIMULATION METHOD TO CHECK |
| B | | REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY |
| 3. | CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - BRAKE ACTUATOR ASSEMBLY) |
(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.
OK:
The connector is securely connected.
(c) Disconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.
(d) Disconnect the A54 brake actuator assembly connector.
(e) Check both the connector case and the terminals for deformation and corrosion.
OK:
No deformation or corrosion.
(f) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A45-40 (+BM) - A54-10 (+BM) | Always | Below 1 Ω |
| A45-40 (+BM) or A54-10 (+BM) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CHECK HARNESS AND CONNECTOR (GND TERMINAL) |
| (a) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
|
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| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT) |
|
| 5. | RECONFIRM DTC |
(a) Reconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.
(b) Reconnect the A54 brake actuator assembly connector.
(c) Clear the DTCs.
Click here
(d) Turn the power switch off.
(e) Turn the power switch on (READY).
(f) Perform a road test.
(g) Check if the same DTC is output.
Click here
| Result | Proceed to |
|---|---|
| DTC C1427 is not output. | A |
| DTC C1427 is output. | B |
| A | | USE SIMULATION METHOD TO CHECK |
| B | | REPLACE BRAKE ACTUATOR ASSEMBLY |
READ NEXT:
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WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE:
Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Audio and Visual System.
Click here
When replacing the radio receiv
