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DTC U0001: Malfunction of CAN Communication Circuit
 
 
 
 
DIAGNOSTIC FUNCTION
TCM conducts bus-off detection.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • TCM cannot receive the periodic communication data.
 
 
MONITOR EXECUTION
  • When 1.05 seconds have elapsed after TCM started
 
 
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • P0703: Malfunction of stoplight switch
  • P0705: Malfunction of transmission range switch
  • P0712, P0713: Malfunction of the transmission fluid temperature sensor
  • P0715: Malfunction of primary pulley speed sensor
  • P0720: Malfunction of secondary pulley speed sensor
  • P0725: Malfunction of engine speed
  • P0740: Malfunction of lockup solenoid valve
  • P0745: Malfunction of line pressure solenoid valve
  • P0840: Malfunction of secondary pressure sensor
  • P1777: Malfunction of stepper motor
Sensor (The sensor below is determined to be normal)
  • Stoplight switch
  • Transmission range switch
  • Primary pulley speed sensor
  • Secondary pulley speed sensor
  • Secondary pressure sensor
 
 
LOGIC FLOW CHARTS (Monitor Sequence)
 
 
DTC SET CONDITIONS
Check Conditions
  • Time after TCM start: more than 1.05 seconds.
  • Voltage of battery: 9 volts or more
  • Voltage of battery: 16 volts or less
Judgment Criteria
  • CAN communication: fail
 
 
OBD-II DRIVE CYCLE PATTERN
Ignition switch: ON (start the engine and keep it for 10 seconds or more)
 
 
PROBABLE CAUSES
  • Malfunction of the CAN bus
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
Use scan tool MB991958 to perform the CAN bus diagnosis.
Is the check result normal?
Intermittent malfunction
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting, Diagnostic Trouble Code Chart ).