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DTC P0725: Malfunction of Engine Speed
 
 
 
 
DIAGNOSTIC FUNCTION
TCM detects malfunction of engine speed received from the ECM by comparing the primary pulley speed with the secondary pulley speed.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Primary pulley speed of 1,000 r/min or more and with the engine speed of 450 r/min or less
  • When the differences in rotation between the engine and the primary pulley, and between the engine and the secondary pulley are 1,000r/min or more during direct-coupled operating
  • CAN communication error occurs between ECM and TCM.
 
 
MONITOR EXECUTION
  • transmission range: D
  • Throttle valve opening: 1/8 or more
  • Voltage of battery: 10 volts or more.
 
 
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • P0705: Malfunction of transmission range switch
  • P0712, P0713: Malfunction of the transmission fluid temperature sensor
  • P0715: Malfunction of primary pulley speed sensor
  • P0740: Abnormality in lockup function
  • P0745: Malfunction of line pressure solenoid valve
  • P0840: Malfunction of secondary pressure sensor
  • P1777: Malfunction of stepper motor
  • U0001: Malfunction of CAN communication circuit
Sensor (The sensor below is determined to be normal)
  • Transmission range switch
  • Transmission fluid temperature sensor
  • Primary pulley speed sensor
  • Secondary pressure sensor
 
 
LOGIC FLOW CHARTS (Monitor Sequence-Input Rationality-Low)
 
 
LOGIC FLOW CHARTS (Monitor Sequence-Input Rationality-High)
 
 
DTC SET CONDITIONS
Check Conditions
  • Transmission range switch position: D.
  • Throttle position sensor voltage: 1.37 volts or more.
  • Primary pulley speed: 1,000 r/min or more.
  • The absolute value of the Primary pulley speed - secondary pulley speed: 1,000 r/min or less.
  • Voltage of battery: 9 volts or more.
  • Voltage of battery: 16 volts or less.
Judgment Criteria
  • Engine revolution [primary pulley speed: 1,000 r/min or more]: less than 450 r/min.
  • The difference of engine speed and primary speed: more than 1,000 r/min. (5 seconds)
  • The difference of engine speed and secondary speed: more than 1,000 r/min. (5 seconds)
 
 
OBD-II DRIVE CYCLE PATTERN
Transmission range: D (Drive the vehicle for 10 seconds or more while the accelerator opening angle is 20% or more)
 
 
PROBABLE CAUSES
  • Malfunction of the CAN bus
  • Malfunction of the engine system
  • Malfunction of TCM
 
 
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?
Go to Step 2.
Go to "CAN Troubleshooting."
 
STEP 2. M.U.T.-III diagnostic trouble code
Check if the engine-related diagnostic trouble code is stored.
Is the check result normal?
Go to Step 3.
Go to "Engine Troubleshooting."
 
STEP 3. Symptom recheck after erasing diagnostic trouble code
Is the check result normal?
Intermittent malfunction
Replace TCM.