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Home >> Toyota >> 2020 >> 86 Base, Automatic Trans >> Repair and Diagnosis (Single Page) >> Body & Frame >> Door Locks >> Smart Key System (Keyless Start) - Diagnostic Codes & Symptom Tests >> SMART KEY SYSTEM (for Start Function) >> Diagnostic Codes >> DTC U0073: Control Module Communication Bus Off; DTC U0100: Lost Communication with ECM / PCM "A"; DTC U0101: Lost Communication with TCM; DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0140: Lost Communication with Body Control Module; DTC U0155: Lost Communication with Instrument Panel Cluster Control Module (Combination Meter); DTC U0401: Invalid Data Received from ECM/PCM "A"; DTC U0422: Invalid Data Received from Body Control Module [03/2017 - ] >> Description
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DTC U0073: Control Module Communication Bus Off; DTC U0100: Lost Communication with ECM / PCM "A"; DTC U0101: Lost Communication with TCM; DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0140: Lost Communication with Body Control Module; DTC U0155: Lost Communication with Instrument Panel Cluster Control Module (Combination Meter); DTC U0401: Invalid Data Received from ECM/PCM "A"; DTC U0422: Invalid Data Received from Body Control Module [03/2017 - ]: Description

These DTCs are stored when there is a CAN communication error between the certification ECU (smart key ECU assembly) and the ECM, TCM, main body ECU (network gateway ECU), combination meter assembly or skid control ECU (brake actuator assembly).

HINT: 

When the cable is disconnected and reconnected to the negative (-) battery terminal, the power source mode returns to the state it was in before the cable was disconnected.

DTC No. DTC Detection Condition Trouble Area DTC Output Confirmation Operation
U0073 CAN communication system malfunction (1-trip detection logic*). CAN communication system Turn the engine switch on (IG) and wait 10 seconds or more.
U0100 CAN communication malfunction between the certification ECU (smart key ECU assembly) and ECM (1-trip detection logic*). ECM Turn the engine switch on (IG) and wait 10 seconds or more.
U0101 CAN communication malfunction between the certification ECU (smart key ECU assembly) and TCM (1-trip detection logic*). TCM Turn the engine switch on (IG) and wait 10 seconds or more.
U0122 CAN communication malfunction between the certification ECU (smart key ECU assembly) and skid control ECU (brake actuator assembly) (1-trip detection logic*). Skid control ECU (brake actuator assembly) Turn the engine switch on (IG) and wait 10 seconds or more.
U0140 CAN communication malfunction between the certification ECU (smart key ECU assembly) and main body ECU (network gateway ECU) (1-trip detection logic*). Main body ECU (network gateway ECU) Turn the engine switch on (IG) and wait 10 seconds or more.
U0155 CAN communication malfunction between the certification ECU (smart key ECU assembly) and combination meter assembly (1-trip detection logic*). Combination meter assembly Turn the engine switch on (IG) and wait 10 seconds or more.
U0401 CAN communication malfunction between the certification ECU (smart key ECU assembly) and ECM (1-trip detection logic*). ECM Turn the engine switch on (IG) and wait 10 seconds or more.
U0422 CAN communication malfunction between the certification ECU (smart key ECU assembly) and main body ECU (network gateway ECU) (1-trip detection logic*). Main body ECU (network gateway ECU) Turn the engine switch on (IG) and wait 10 seconds or more.

*: Only output while a malfunction is present and the engine switch is on (IG)

VEHICLE CONDITION AND FAIL-SAFE FUNCTION WHEN MALFUNCTION DETECTED

DTC Code Vehicle Condition when Malfunction Detected Fail-safe Function when Malfunction Detected
U0073 There is no effect on vehicle behavior. -
U0100 There is no effect on vehicle behavior. If the following conditions are met, it is determined that the malfunction is not in the direct line (TACH) but in CAN communication. 
  • When the engine switch is pressed, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking.
  • When the engine switch is pressed and held, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking.

If the following conditions are met, it is determined that there is a malfunction in both CAN communication and the direct line (TACH). 
  • When the engine switch is pressed, the engine stops cranking after 6 seconds.
  • When the engine switch is pressed and held, the engine remains cranking for up to 30 seconds.
U0101 There is no effect on vehicle behavior. -
U0122 There is no effect on vehicle behavior. -
U0140 Doors cannot be locked or unlocked.
The warning (wireless buzzer) does not sound.		 -
U0155 The warning (meter buzzer) does not sound and the meter does not indicate a warning. -
U0401 There is no effect on vehicle behavior. -
U0422 Doors cannot be locked or unlocked.
The warning (wireless buzzer) does not sound.		 -
RELATED DATA LIST AND ACTIVE TEST ITEMS

DTC Data List Item Active Test Item
U0073
U0100
U0101
U0122
U0140
U0155
U0401
U0422		 - -
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