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Home >> Audi >> 2015 >> A4 Prestige >> Repair and Diagnosis >> External Pages >> Different car >> Section 469 (Smart Access System (Keyless Start) (Diagnostic Codes & Symptom Tests)) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) >> DTC U0100: Lost Communication with ECM; DTC U0140: Lost Communication with Main Body ECU; DTC U0142: Lost Communication with Main Body ECU; DTC U0155: Lost Communication with Combination Meter; DTC U0293: Lost Communication with HV ECU [08/2013 - ] >> Description

DTC U0100: Lost Communication with ECM; DTC U0140: Lost Communication with Main Body ECU; DTC U0142: Lost Communication with Main Body ECU; DTC U0155: Lost Communication with Combination Meter; DTC U0293: Lost Communication with HV ECU [08/2013 - ]: Description

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

These DTCs are stored when there is a CAN communication error between the power management control ECU and the certification ECU (smart key ECU assembly).

HINT: 

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

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
U0100 CAN communication error between the certification ECU (smart key ECU assembly) and power management control ECU (1-trip detection*) Power management control ECU Turn the power switch on (IG) and wait 10 seconds or more.
U0140 CAN communication error between the power management control ECU and main body ECU (1-trip detection*) Main body ECU (multiplex network body ECU) Always
U0142 CAN communication error between the certification ECU (smart key ECU assembly) and main body ECU (1-trip detection*) Main body ECU (multiplex network body ECU) Always
U0155 CAN communication error between the power management control ECU or certification ECU (smart key ECU assembly) and combination meter assembly (1-trip detection*) Combination meter assembly Turn the power switch on (IG) and wait 10 seconds or more.
U0293 CAN communication error between the certification ECU (smart key ECU assembly) and power management control ECU (1-trip detection*) Power management control ECU Turn the power switch on (IG) and wait 10 seconds or more.
VEHICLE CONDITION AND FAIL-SAFE FUNCTION WHEN MALFUNCTION DETECTED

DTC Code Vehicle Condition when Malfunction Detected Fail-safe Function when Malfunction Detected
U0100 There is no effect on vehicle behavior. -
U0140 The warning (meter buzzer) does not sound and the meter does not indicate a warning. -
U0142
  • Doors cannot be locked or unlocked. The warning (wireless buzzer) does not sound.
  • The warning (meter buzzer) does not sound and the meter does not indicate a warning.
-
U0155
  • The warning (meter buzzer) does not sound and the meter does not indicate a warning. (When the smart key ECU stores the DTC.)
  • There is no effect on vehicle behavior. (When the power management control ECU stores the DTC.)
-
U0293 The warning (meter buzzer) does not sound and the meter does not indicate a warning. -