DIAGNOSIS FUNCTION


ACC/FCM-ECU has the following functions for easier system checks.

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

CHECK OF THE 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
 Odometer(Last time fail detect.)
 Total driving distance when the diagnosis code is set at the last trouble judgement.
 km
3
 Detection counter
 How many times the same diagnosis code was set (counted as "0" when the malfunction occurs for the first time).
 times
4
 Ignition cycle
 How many times the ignition switch is turned "ON" since the diagnosis code is set as "historic fault".
 times
5
 ECU power supply voltage
 Power supply voltage to the ECU when the diagnosis code is set.
 V
6
 RADAR temperature
 Internal temperature in the radar when the diagnosis code is set.
 °C
7
 Outside temperature
 Ambient temperature when the diagnosis code is set.
 °C
8
 Steering wheel angle
 Steering wheel angle, which is received from the steering wheel sensor when the diagnosis code is set.
 deg
9
 Accelerator pedal position
 Accelerator pedal opening angle, which is received from the engine-ECU when the diagnosis code is set.
 %
10
 Yaw rate
 Yaw rate value, which is received from the yaw rate sensor when the diagnosis code is set.
 deg/s
11
 AS&G status
 Not used.
12
 A.S.C. status
 The ASTC status when the diagnosis code is set.
 -
13
 Master cylinder pressure
 The pressure in the master cylinder, which is received from the master cylinder pressure sensor when the diagnosis code is set.
 MPa
14
 Longitudinal acceleration
 Longitudinal acceleration when the diagnosis code is set.
 m/s2
15
 Lateral acceleration
 Lateral acceleration when the diagnosis code is set.
 m/s2
16
 Vehicle speed
 Vehicle speed when the diagnosis code is set.
 km/h
17
 FCM function
 Forward Collision Mitigation (FCM) system status when the diagnosis code is set
 -
18
 RADAR blockage state
 Radar status when the diagnosis code is set
 -
19
 FCM:Auto brake request
 Request for automatic braking when the diagnosis code is set
 -
20
 FCM:Auto brake acknowledge
 Response status of automatic braking when the diagnosis code is set
 -
21
 FCM:Target deceleration
 Target deceleration when the diagnosis code is set
 m/s2
22
 FCM:Brake prefill request
 Request status for pre-fill brake when the diagnosis code is set
 -
23
 FCM:Brake assist request
 Request status for brake assist when the diagnosis code is set
 -
24
 FCM:Engine brake request
 Not used.
25
 FCM:Brake prefill acknowledge
 Response status for pre-fill brake when the diagnosis code is set
 -
26
 FCM:Brake assist acknowledge
 Response from brake assist when the diagnosis code is set
 -
27
 FCM:Engine brake acknowledge
 Not used.
28
 FCM:Standstill state
 Not used.
29
 Brake switch
 Stop lamp switch status when the diagnosis code is set.
 -
30
 Ignition switch
 Ignition switch status (IG1) when the diagnosis code is set.
 -
31
 ACC system status
 ACC system status when the diagnosis code is set.
 -
32
 Auto brake status
 Status of automatic braking controlled by ASTC when the diagnosis code is set.
 -
33
 ACC:Set speed
 Set speed
 -
34
 ACC:Set speed (unit)
 Unit of set speed: km/h or mph
 -
35
 Vertical alignment (Current)
 How much the radar axis is compensated vertically when the diagnosis code is set.
 deg
36
 Horizontal alignment (Current)
 How much the radar axis is compensated horizontally when the diagnosis code is set.
 deg

FAIL-SAFE FUNCTIONS




If the ACC/FCM-ECU determines that the system fails, the ECU will activate the warning message ("ACC TEMPORARILY NOT AVAILABLE", "ACC SERVICE REQUIRED" or "ACC/FCM RADAR BLOCKED") on the multi-information display.

Activating the warning message when a malfunction occurs


Diagnosis code No.
 Inspection item
 Message "ACC TEMPORARILY NOT AVAILABLE"
 Message "ACC SERVICE REQUIRED"
 Message "ACC/FCM RADAR BLOCKED"
C1394
 INCOMP.learn neutral (SAS)
 ON
 OFF
 OFF
C1707
 Implausible coding data
 ON
 OFF
 OFF
C1750
 ACC/FCM voltage out of range
 ON
 OFF
 OFF
C1751
 ACC/FCM ECU failure
 OFF
 ON
 OFF
C1752*1
 ACC/FCM radar TEMP.out of range
 ON
 OFF
 OFF
C1753*1
 ACC/FCM radar blockage detected
 OFF
 OFF
 ON
C1754
 ACC/FCM radar CAL. Not COMP
 ON*2
 OFF
 OFF
C1772
 Alignment sensor too far (Right)
 ON
 OFF
 OFF
C1773
 Alignment sensor too far (Left)
 ON
 OFF
 OFF
C1774
 Alignment sensor too far (Lower)
 ON
 OFF
 OFF
C1775
 Alignment sensor too far (Upper)
 ON
 OFF
 OFF
C1776
 ACC system fail detected (ENG)
 OFF
 ON
 OFF
C1777
 System fail detected (ASC)
 OFF
 ON
 OFF
C1778
 Vehicle speed signal failure
 OFF
 ON
 OFF
C1781
 SAS internal fail
 OFF
 ON
 OFF
C1782
 SAS signal fail
 OFF
 ON
 OFF
C1783
 ACC distance switch fixed ON
 OFF
 OFF
 OFF
C1785
 Fault detect signal fail
 OFF
 ON
 OFF
C1787
 APS signal
 OFF
 ON
 OFF
C1791
 Vehicle speed signal SNA detected
 ON
 OFF
 OFF
C1792
 Brake M/C PRS. signal (invalid)
 ON
 OFF
 OFF
C1794
 Longitudinal G signal (invalid)
 ON
 OFF
 OFF
C1795
 Yaw rate signal (invalid)
 ON
 OFF
 OFF
C1796
 APS signal (invalid)
 ON
 OFF
 OFF
C1808
 Noise error
 ON
 OFF
 OFF
C2256
 Brake switch signal fail
 OFF
 ON
 OFF
C2257
 ASTC signal failure 1
 OFF
 ON
 OFF
C2258
 ASTC signal failure 2
 OFF
 ON
 OFF
C2259
 ASTC signal failure 3
 OFF
 ON
 OFF
C2260
 ASTC signal failure 4
 OFF
 ON
 OFF
C2261
 ASTC signal failure 5
 OFF
 ON
 OFF
C2262
 SAS offset threshold exceed
 ON
 OFF
 OFF
C2263*1
 Yaw rate offset threshold exceed
 ON
 OFF
 OFF
C2264
 Estimated tyre size exceed
 ON
 OFF
 OFF
C2265
 Unavailable reference velocity
 ON
 OFF
 OFF
C2266
 Unavailable of Yaw rate quality
 ON
 OFF
 OFF
C2267
 Wheel speed signal fail
 ON
 OFF
 OFF
C2268
 Distance travelled signal fail
 ON
 OFF
 OFF
C2270
 Current gear signal fail
 ON
 OFF
 OFF
C2271
 SAS signal fail
 ON
 OFF
 OFF
C2272
 Delta SAS signal fail
 ON
 OFF
 OFF
C2273
 T/F state signal
 ON
 OFF
 OFF
C2274
 Reduction gear state signal
 ON
 OFF
 OFF
C2275
 Rear diff. lock state signal
 ON
 OFF
 OFF
C2276
 Brake switch signal
 ON
 OFF
 OFF
C2277
 Engine status signal
 ON
 OFF
 OFF
C2278
 ACC/FCM signal (A/T No response)
 OFF
 ON
 OFF
C2296
 CAN buffer error
 OFF
 ON
 OFF
C2297
 CAN transmit error
 OFF
 ON
 OFF
U0100
 Engine CAN timeout
 OFF
 ON
 OFF
U0101
 T/M CAN timeout
 OFF
 ON
 OFF
U0114
 Transfer-ECU CAN timeout
 OFF
 ON
 OFF
U0121
 ASTC CAN timeout
 OFF
 ON
 OFF
U0126
 SAS CAN timeout
 OFF
 ON
 OFF
U0141
 ETACS CAN timeout
 OFF
 ON
 OFF
U0146
 Gateway CAN timeout
 OFF
 OFF
 OFF
U0155
 Meter CAN timeout
 OFF
 ON
 OFF
U0317
 EPB CAN timeout
 OFF
 OFF
 OFF
U1195
 Coding not completed
 ON
 OFF
 OFF
-*3
 -
 ON
 OFF
 OFF
-*4
 -
 OFF
 ON
 OFF
note
  • *1: The diagnosis code may not be detected when the ACC system is switched OFF.
  • *2: The ACC main indicator lamp flashes at approximately 1 Hz when the radar has not been calibrated, and at approximately 2 Hz while it is calibrated.
  • *3: When the ACC/FCM-ECU is at bus off, or in some specific condition (e.g., Engine-ECU or A/T-ECU temporarily stopped ACC), "ACC TEMPORARILY NOT AVAILABLE" will be displayed.
  • *4: When the ACC/FCM ECU is in some specific condition (e.g., ASTC-ECU temporarily stopped ACC), "ACC SERVICE REQUIRED" will be displayed.

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.