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Home >> Lexus >> 2022 >> NX 350 Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Stop And Start System - Diagnostics - Introduction (1 Of 2) >> Stop And Start System >> Fail-Safe Chart [11/2021 - 03/2023] >> Fail-Safe Chart [11/2021 - 03/2023]

Fail-Safe Chart [11/2021 - 03/2023]

If any of the following DTCs are stored, the engine stop and start ECU enters fail-safe mode to preserve vehicle operability.

DTC Component Fail-safe Operation Fail-safe Deactivation Condition
P0335-62 Open in engine speed signal circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 All of the following conditions are met for 10 seconds or more:
  • Normal communication with ECM
  • Engine speed (pulse signal) 500 rpm or higher
  • Engine speed (communication signal) 500 rpm or higher
  • Difference between engine speed from pulse signal and engine speed from communication signal is less than 300 rpm
P0555-00
P0555-2A
  • Vacuum sensor assembly
  • Brake booster assembly
  • Vacuum hose (brake booster hose)
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 One of the following conditions is met:
  • Vacuum changes while the brake pedal is depressed
  • Vacuum changes a specified number of times while the vehicle is being driven faster than a certain vehicle speed
P0555-11
P0555-15		 Vacuum sensor assembly circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Sensor output is within standard range
P0606-29 Engine stop and start ECU
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Pass condition detected and ignition switch turned to ON
P060B-1C
P060B-49
P060B-71		 Analog to digital converter (Engine stop and start ECU) Stop and start control is prohibited Pass condition detected and ignition switch turned to ON
P0615-19 ST relay circuit Stop and start control is prohibited Pass condition detected and DTCs are cleared
P0615-62 Starter circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with ECM returns to normal and one of the following conditions is met:
  • The STA signal detected by the ECM and STA signals detected by the engine stop and start ECU are on for 0.3 seconds
  • The STA signal detected by the ECM and STA signals detected by the engine stop and start ECU are off for 5 seconds
P0942-96 Oil pump with solenoid assembly circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Pass condition detected and DTCs are cleared
P1644-00
  • Starter drive circuit
  • ST NO. 1 relay
  • Engine stop and start ECU
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Voltage of engine stop and start ECU internal drive circuit for starter is correct when engine is idling and restarted
P1644-9E Engine stop and start ECU
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Pass condition detected and ignition switch turned to ON
P2530-14 IG signal circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 All of the following conditions are met for 10 seconds or more:
  • Ignition switch ON
  • Normal communication with ECM
P2796-12
P2796-14
P2797-96		 Oil pump with solenoid assembly circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Pass condition detected and ignition switch turned to ON
P30DF-62
P30EF-4B
P323A-00
P323A-16
P323A-A2
P323B-29
P323B-38		 Backup boost converter circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Pass condition detected and DTCs are cleared
P323A-19 Backup boost converter circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
  • Pass condition detected and ignition switch turned to ON
  • DTCs (for overcurrent caused by audio volume setting) are cleared
P33B3-00 External backup boost converter (eco run vehicle converter assembly) circuit
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 1 second after external backup boost converter (eco run vehicle converter assembly) circuit becomes idle
U0100-87 CAN communication (ECM)
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 2 seconds or more
U0126-87 CAN communication (steering sensor)
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 2 seconds or more
U0129-87 CAN communication (skid control ECU (brake actuator assembly))
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 4.4 seconds or more
U0140-87 CAN communication (main body ECU (multiplex network body ECU))
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 7.2 seconds or more
U0151-87 CAN communication (airbag sensor assembly)
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 21.2 seconds or more
U0155-87 CAN communication (combination meter assembly)
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 21.2 seconds or more
U0164-87 CAN communication (air conditioning amplifier assembly)
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 21.2 seconds or more
U1170-87 Local CAN communication (skid control ECU (brake actuator assembly))
  • Stop and start control is prohibited
  • Engine is automatically restarted if a DTC is stored while the engine is stopped by stop and start control
 Communication with engine stop and start ECU continues for 21.2 seconds or more
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