Fail-Safe List
WARNING: This page is about a different car, the 2014 Subaru BRZ. However, it is still accessible from the selected car via links, so may be relevant.
- Fail-safe function
- If a failure occurs on any of the bus (communication line) due to short circuit and other reasons, the fail safe function switches the process on the defective bus to a predefined bus to protect against malfunction.
- Behavior of each system in case of lost communication (For details, refer to the
description of each system)
Function Control master (Main ECM that controls the process) Relevant ECMs Behavior in case of lost communication Notification to driver Notification method Diagnostic codes ([ECM which saves DTC]) Speed display (Display the data on speed meter based on vehicle speed signal sent by the brake actuator assembly) Combination meter assembly Brake actuator assembly Assume the input signal indicates 0 km/h Yes - Display 0 km/h on the speed meter
- Stop the driving monitor calculation
U0122
[Combination meter assembly]Odo/trip meter
(Receive vehicle speed signal and display the travel distance)Combination meter assembly Brake actuator assembly Stop calculation and continue to display the last data until IG-OFF No - U0122
[Combination meter assembly]Tachometer
(Receive the engine speed signal and display the data on tachometer)Combination meter assembly Engine control computer Assume the input signal indicates 0 rpm Yes Display 0 rpm on the tachometer U0100
[Combination meter assembly]Airbag
(Turn ON/OFF the airbag warning light)Combination meter assembly Airbag sensor assembly Assume the input signal indicates "Active" Yes Turn ON the airbag warning light U0151
[Combination meter assembly]EPS warning
(Turn ON/OFF the EPS warning light)Combination meter assembly Power steering computer assembly Assume the input signal indicates "Active" Yes Turn ON the EPS warning light U0131
[Combination meter assembly]SLIP warning
(Turn ON/OFF the SLIP warning light)Combination meter assembly Brake actuator assembly Assume the input signal indicates "Active" Yes Turn ON the SLIP warning light U0122
[Combination meter assembly]Smart function
(Smart lock/smart unlock/smart trunk open)Collation ECM (Smart key computer assembly) - Main body ECM (Multiplex network body computer)
- Combination meter assembly
Activate the smart unlock-retry Yes - Disable the smart lock/smart unlock/smart trunk open
- Disable the smart alert (lockout, key theft, key reminder) and disable the key lockout prevention control
- Disable the smart illumination
U0140, U0155, U0422 [Collation ECM (Smart key computer assembly)] Engine ignition SW light control
(Turn ON/OFF the engine ignition switch light)Collation ECM (Smart key computer assembly) Main body ECM (Multiplex network body computer) - If the engine ignition SW light is ON (with dome light): turn OFF
- If DC cut fuse is pulled and the engine ignition SW light is ON (panel light): turn OFF
Yes - If the engine ignition SW light is ON (with dome light): turn OFF
- If DC cut fuse is pulled and the engine ignition SW light is ON (panel light): turn OFF
U0140, U0422
[Collation ECM (Smart key computer assembly)]Push button start
(Power supply switching)Collation ECM (Smart key computer assembly) - Main body ECM (Multiplex network body computer)
- Combination meter assembly
- Engine control computer
- Yes Do not display the start operation U0100, U0140, U0155, U0422
[Collation ECM (Smart key computer assembly)]Electric load control
(Idle-up is enabled due to electric load, etc.)Engine control computer - Main body ECM (Multiplex network body computer)
- Air conditioner amplifier assembly
Disable idle-up due to electric load, etc. Yes Idle speed changes - Air conditioner cooperation (Enable idle-up/air conditioner cut control via compressor load) Engine control computer Air conditioner amplifier assembly Disable the air conditioner cooperation (no idle-up) Yes Stop the air conditioner - Integrated control (VSC) (By estimating the required driving force (torque) based on the acceleration, control the driving force (torque) characteristics as required to realize stability under constant velocity driving, improve starting, reacceleration, and acceleration) Engine control computer - Collation ECM (Smart key computer assembly)
- Brake actuator assembly
- Spiral cable sub-assembly
- Brake actuator assembly
Disable the functions to estimate the required driving force (torque) based on the acceleration and control the driving force (torque) characteristics as required to realize stability under constant velocity driving, improve starting, reacceleration, and acceleration Yes Disable the functions to estimate the required driving force (torque) based on the acceleration and control the driving force (torque) characteristics as required to realize stability under constant velocity driving, improve starting, reacceleration, and acceleration - ECT system indicator display
(Display shift, S/W, mode on the meter)Transmission control computer assembly Combination meter assembly Disable the indicators Yes Indicators are OFF - AI-SHIFT control
(Automatic transmission control to improve engine braking force and acceleration)Transmission control computer assembly Brake actuator assembly AI-SHIFT control is disabled No - - N control
(Reduce the engine load and activate idle-up)Transmission control computer assembly Brake actuator assembly Disable N control No - - Coast down shift
(Switch the coast down speed change point according to air conditioner load)Transmission control computer assembly Air conditioner amplifier assembly Coast down shock becomes more apparent No - - Shift-up delay due to heating request
(Activate the shift-up delay due to heating request)Transmission control computer assembly Air conditioner amplifier assembly Shift-up delay due to heating request is disabled No - - ABS/VSC/TRC control
(Anti-wheel-lock in sudden braking)
(Improve stability of the vehicle to protect against skidding while turning and wheel slip when starting the vehicle)Brake actuator assembly - Engine control computer
- Spiral cable sub-assembly
- Airbag sensor assembly
ABS/VSC/TRC control is disabled Yes - Brake warning light is ON
- ABS warning light is ON
- Slip indicator light is ON
U0100
U0126
[Brake actuator assembly]EPS control
(Adaptive torque control in response to vehicle speed)Power steering computer assembly Engine control computer Assist stops or degraded (steering wheel becomes heavy) Yes - U0100
[Power steering computer assembly]Brake actuator assembly ESP indicator is ON U0122
U0416
[Power steering computer assembly]Air conditioner control
(Water temperature correction control)Air conditioner amplifier assembly Engine control computer - Temperature information (IG ON): use the default value (80°C)
- Engine type (IG ON): use the default value (depends on the model)
- IG-OFF: none
No - U0100
U0401
[Air conditioner amplifier assembly]Simple load control
(Restrict the simple electric load control depending on load control level)Air conditioner amplifier assembly Power steering computer assembly - The last data is retained while IG-ON (if reset, the load control is disabled)
- IG-OFF: none
No - U0100
U0401
[Air conditioner amplifier assembly]Panel dimmer control
(A/C control pattern switch, HCAV control switch, indicator dimmer control)Air conditioner amplifier assembly Main body ECM (Multiplex network body computer) - The last data is retained while IG-ON (if reset, the load control is disabled)
- IG-OFF: none
Yes Rear defroster switch is disabled U0140
U0422
[Air conditioner amplifier assembly]Destination identification control
(Identify the destination)Air conditioner amplifier assembly Main body ECM (Multiplex network body computer) - The last data is retained while IG-ON
- IG-OFF: none
Yes Rear defroster switch is disabled U0140
U0422
[Air conditioner amplifier assembly]Ambient temperature correction control
(Switch the operation status of air conditioner and correct the ambient temperature display value based on the vehicle signal)Air conditioner amplifier assembly Combination meter assembly - SPD (IG ON): control using the default value (0 km)
- IG-OFF: none
No - The consistency between the ambient temperature and the display value is reduced
- The level of A/C air flow volume correction goes down
U0155
U0423
[Air conditioner amplifier assembly]Event data recorder (EDR) (If EDR record criteria is met, the status data regarding the vehicle speed, accelerator pedal opening angle, and shift position is logged) Airbag sensor assembly - Brake actuator assembly
- Engine control computer
"Invalid data" is logged in the event data recorder (EDR) No - -