Lexus ES: EPB Switch Malfunction (C13B4)
DESCRIPTION
When the electric parking brake switch is pushed, a lock request signal is sent from the parking brake ECU (brake actuator assembly) to the parking brake actuator assembly. When the electric parking brake switch is pulled, a release request signal is sent from the parking brake ECU (brake actuator assembly) to the parking brake actuator assembly.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory | Note |
|---|---|---|---|---|---|
| C13B4 | EPB Switch Malfunction |
|
| DTC stored | An electric parking brake system malfunction is displayed on the multi-information display. |
| Vehicle Condition | |||
|---|---|---|---|
| Pattern 1 | Pattern 2 | ||
| Diagnosis Condition | - | - | - |
| Malfunction Status | Parking brake switch open or short circuit is detected | ○ | - |
| Parking brake switch stuck malfunction | - | ○ | |
| Detection Time | 1 second or more | - | |
| Number of Trips | 1 trip | 1 trip | |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- The electric parking brake may still operate up to 20 seconds after the power switch is turned off. Before disconnecting connectors or fuses, turn the power switch off and wait 20 seconds or more.
- The parking brake indicator light blinks (red) when the power switch is turned on (IG) after replacing the parking brake ECU (brake actuator assembly). Operate the electric parking brake switch assembly to turn off the parking brake indicator light (red).
PROCEDURE
| 1. | INSPECT ELECTRIC PARKING BRAKE SWITCH ASSEMBLY |
(a) Inspect the electric parking brake switch assembly.
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| NG | .gif) | REPLACE ELECTRIC PARKING BRAKE SWITCH ASSEMBLY |
|
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| 2. | CHECK HARNESS AND CONNECTOR (PARKING BRAKE ECU (BRAKE ACTUATOR ASSEMBLY) - ELECTRIC PARKING BRAKE SWITCH ASSEMBLY) |
(a) Disconnect the G29 electric parking brake switch assembly connector.
(b) Disconnect the A54 parking brake ECU (brake actuator assembly) connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A54-14 (SWI1) - G29-7 (SWI1) | Always | Below 1 Ω |
| A54-20 (SWO1) - G29-8 (SWO1) | Always | Below 1 Ω |
| A54-24 (SWI2) - G29-1 (SWI2) | Always | Below 1 Ω |
| A54-22 (SWO2) - G29-2 (SWO2) | Always | Below 1 Ω |
| A54-14 (SWI1) or G29-7 (SWI1) - Body ground | Always | 10 kΩ or higher |
| A54-20 (SWO1) or G29-8 (SWO1) - Body ground | Always | 10 kΩ or higher |
| A54-24 (SWI2) or G29-1 (SWI2) - Body ground | Always | 10 kΩ or higher |
| A54-22 (SWO2) or G29-2 (SWO2) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK DTC |
(a) Clear the DTCs.
Chassis > Electric Parking Brake > Clear DTCs(b) Turn the power switch off.
(c) Turn the power switch on (IG).
(d) Check for DTCs.
Chassis > Electric Parking Brake > Trouble Codes| Result | Proceed to |
|---|---|
| DTCs are output | A |
| DTCs are not output | B |
| A | | REPLACE PARKING BRAKE ECU (BRAKE ACTUATOR ASSEMBLY) |
| B | | USE SIMULATION METHOD TO CHECK |
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