DIAGNOSTIC FUNCTION


Electric parking brake ECU has the following functions for easier system checks.

All the above items can be diagnosed using M.U.T.-III.

CHECK OF FREEZE FRAME DATA


The freeze frame data can be checked by using the M.U.T.-III.
When detecting fault and setting the diagnosis code, the ECU connected to CAN bus line obtains the data before the determination of the diagnosis code and the data when the diagnosis code is determined, and then stores the ECU status of that time. By analysing each data from M.U.T.-III, the troubleshooting can be performed more efficiently. The displayed items are as the table below.

Display item list
Item No.
 Item name
 Data item
 Unit
1
 Odometer
 Total driving distance after the diagnosis code is generated
 km
2
 Ignition cycle
 Number of times the ignition switch is turned ON or LOCK (OFF) after the past failure transition
 Number of counts is displayed.
3
 Tension 1 sensor monitor value
 A value which tension 1 sensor monitors when a diagnosis code is set.
 V
4
 Tension 2 sensor monitor value
 A value which tension 2 sensor monitors when a diagnosis code is set.
 V
5
 Target tension
 Tension of the parking brake cable (target tension), which the vehicle can be held at, when the diagnosis code is set.
 N
6
 Control vehicle speed
 Vehicle speed (wheel speed) when the diagnosis code is generated
 r/min
7
 Power supply voltage
 Voltage of power supply when the diagnosis code is generated
 V
8
 Parking brake status
 Electric parking brake control when the diagnosis code is generated: Release/Lock/Lock -> Release/Release -> Lock/Undefined
 -
9
 EPB switch:LOCK 1 SW
 Electric parking brake switch (Lock switch 1) condition when the diagnosis code is generated: OFF/ON/Open/Short
 -
10
 EPB switch:LOCK 2 SW
 Electric parking brake switch (Lock switch 2) condition when the diagnosis code is generated: OFF/ON/Open/Short
 -
11
 EPB switch:RELEASE 1 SW
 Electric parking brake switch (Release switch 1) condition when the diagnosis code is generated: OFF/ON/Open/Short
 -
12
 EPB switch:RELEASE 2 SW
 Electric parking brake switch (Release switch 2) condition when the diagnosis code is generated: OFF/ON/Open/Short
 -
13
 Ignition switch
 Ignition switch condition when the diagnosis code is generated: OFF/ON
 -
14
 Acceleration pedal
 Accelerator pedal position sensor condition when the diagnosis code is generated: OFF/ON
 -
15
 Brake switch
 Stop lamp switch condition when the diagnosis code is generated: OFF/ON
 -
16
 Shift information
 Shift condition when the diagnosis code is generated: P/R/N/D
 -

FAIL-SAFE FUNCTIONS


When the electric parking brake ECU detects any malfunction in the system, the ECU will activate the brake warning lamp, the electric parking brake warning lamp and the electric parking brake switch indicator lamp to inform the driver that the electric parking brake is disabled.
In addition, the ECU displays a warning notice on the multi-information display in the combination meter.

Illumination condition of warning lamp, indicator lamp and multi information display in case of failure


Diagnosis code No.
 Inspection item
 Brake warning lamp
 Electric parking brake warning lamp
 Multi information display
 Electric parking brake switch indicator lamp
C1271
 Motor drive circuit
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
C1471
 Stop lamp switch
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
C1607
 ECU failure
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
C1861
 Power supply low voltage
 Flash (1 Hz)
 OFF
 -
 Flash (1 Hz)
C2250
 Actuator malfunction
 Flash (1 Hz)
 ON
 PARKING BRAKE SERVICE REQUIRED
 Flash (1 Hz)
C2251
 Tension sensor malfunction
 Flash (1 Hz)
 ON
 PARKING BRAKE SERVICE REQUIRED
 Flash (1 Hz)
C2252
 +B voltage malfunction
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
C2253
 EPB SW malfunction
 OFF /Flash (1 Hz)*1
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF /Flash (1 Hz)*1
C2254
 IG SW malfunction
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0100
 Engine CAN timeout
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0101
 T/M CAN timeout
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0121
 ABS/ASC CAN timeout
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0141
 ETACS CAN timeout
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0155
 Meter CAN timeout
 OFF
 OFF
 -
 OFF
U0401
 Engine (CAN message)
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0402
 T/M (CAN message)
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U0415
 ABS/ASC (CAN message)
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
U1073
 Bus-off
 OFF
 ON
 PARKING BRAKE SERVICE REQUIRED
 OFF
-
 The power supply voltage is abnormal*2.
 Flash (1 Hz)
 OFF
 -
 Flash (1 Hz)
-
 The system detects a continuous operation of the electric parking brake (to protect the electric motor from overheat) *3
 Flash (1 Hz)
 OFF
 PARKING BRAKE TEMPORARILY NOT AVAILABLE
 Flash (1 Hz)
note
  • *1: The lamp will flash if all of the four lock and release circuits for the electric parking brake switch are open.
  • *2: The power supply voltage is high or excessively low.
  • *3: If you operate the electric parking brake switch repeatedly in a short period of time, a warning screen will be displayed and the electric parking brake may be disabled temporarily. In this case, you have to wait for approx. one minute after the warning screen disappears until the switch can be operated.

Under lock, release and emergency brake*1 in case of failure


Diagnosis code No.
 Inspection item
 Lock
 Release
 Emergency brake*1
C1271
 Motor drive circuit
 Prohibited
 Prohibited
 Prohibited
C1471
 Stop lamp switch
 Enabled
 Enabled
 Enabled
C1607
 ECU failure
 Enabled/Prohibited
 Enabled/Prohibited
 Enabled/Prohibited
C1861
 Power supply low voltage
 Prohibited
 Enabled
 Prohibited
C2250
 Actuator malfunction
 Prohibited
 Prohibited*4
 Prohibited
C2251
 Tension sensor malfunction
 Prohibited
 Prohibited*4
 Prohibited
C2252
 +B voltage malfunction
 Prohibited
 Prohibited
 Prohibited
C2253
 EPB SW malfunction
 Prohibited
 Prohibited*5
 Enabled/Prohibited
Enabled*6
C2254
 IG SW malfunction
 Enabled
 Enabled
 Enabled
U0100
 Engine CAN timeout
 Enabled
 Enabled
 Enabled
U0101
 T/M CAN timeout
 Enabled
 Enabled
 Enabled
U0121
 ABS/ASC CAN timeout
 Prohibited
 Enabled
 Enabled/Prohibited
U0141
 ETACS CAN timeout
 Enabled
 Enabled
 Enabled
U0155
 Meter CAN timeout
 Enabled
 Enabled
 Enabled
U0401
 Engine (CAN message)
 Enabled
 Enabled
 Enabled
U0402
 T/M (CAN message)
 Enabled
 Enabled
 Enabled
U0415
 ABS/ASC (CAN message)
 Enabled/Prohibited
 Enabled
 Enabled/Prohibited
U1073
 Bus-off
 Prohibited
 Enabled
 Enabled
-
 The power supply voltage is abnormal*2.
 Prohibited
 Prohibited
 Prohibited
-
 The system detects a continuous operation of the electric parking brake (to protect the electric motor from overheat) *3
 Prohibited
 Enabled
 Prohibited
note
  • *1: The emergency brake will be activated when the brake pedal depression is not enough to decelerate the vehicle.
  • *2: The power supply voltage is high or excessively low.
  • *3: If you operate the electric parking brake switch repeatedly in a short period of time, a warning screen will be displayed and the electric parking brake may be disabled temporarily. In this case, you have to wait for approx. one minute after the warning screen disappears until the switch can be operated.
  • *4: Release fully only once.
  • *5: The release circuit of the electric parking brake switch fails.
  • *6: The lock circuit of the electric parking brake switch fails.

HOW TO READ DIAGNOSIS CODE


Refer to GROUP 00 - How to Use Troubleshooting and Inspection Service Points .

HOW TO ERASE DIAGNOSIS CODE


Refer to GROUP 00 - How to Use Troubleshooting and Inspection Service Points .