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DTC P0971: Malfunction of the Primary Pressure Solenoid Valve (high input)
 
 
 
 
DIAGNOSTIC FUNCTION
The TCM monitors the primary pressure solenoid valve circuit for open or short to power supply.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • All the conditions listed below remain for 0.2 seconds.
    • The primary pressure solenoid valve command current is 750 mA or more.
    • The primary pressure solenoid valve current, which the TCM monitors, is 200 mA or less.
    • The solenoid valve drive circuit is not shorted to ground.
  • All the conditions listed below remain for 0.2 seconds.
    • The solenoid valve drive circuit is not shorted to ground.
    • The solenoid valve drive circuit system is defective.
 
 
MONITOR EXECUTION
  • 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)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
LOGIC FLOW CHARTS (Monitor Sequence)
 
 
DTC SET CONDITIONS
Check Conditions
  • Voltage of battery: 10 volts or more.
Judgment Criteria
  • Primary pressure solenoid valve actual current: 200 mA or less (0.2 seconds).
  • Primary pressure solenoid valve target current + F/B adjust value: 750 mA or more (0.2 seconds).
 
 
OBD-II DRIVE CYCLE PATTERN
Ignition switch: ON (start the engine and keep it for 5 seconds or more)
 
 
PROBABLE CAUSES
  • Malfunction of the valve body assembly (Faulty primary pressure solenoid valve)
  • Damaged wiring harness and connectors
  • Malfunction of TCM
 
 
DIAGNOSIS
STEP 1. Voltage measurement at TCM connector (PRLS terminal)
(1) Disconnect the TCM connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between the TCM connector (PRLS terminal) and body ground.
OK: 0 V
Is the check result normal?
Go to Step 2.
: Repair the connector(s) or the wiring harness (PRLS line between the CVT assembly connector and the TCM connector).
 
STEP 2. Check for open circuit in PRLS line between the CVT assembly connector and the TCM connector
Is the check result normal?
Go to Step 3.
Repair the connector(s) or the wiring harness.
 
STEP 3. Primary pressure solenoid valve check
Refer to .
Is the check result normal?
Go to Step 5.
Go to Step 4.
 
STEP 4. Check for open circuit in power supply line between the CVT assembly connector and the valve body harness connector (primary pressure solenoid valve line)
Refer to .
Is the check result normal?
Replace the valve body assembly. (Refer to )
Replace the valve body harness. (Refer to )
 
STEP 5. Symptom recheck after erasing diagnostic trouble code
Is the diagnostic trouble code set?
Replace the TCM.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).