[Previous][Next]
DTC P0974: Malfunction of the Low Brake Solenoid Valve (Open Circuit/Short to Power Supply)
 
 
 
 
DIAGNOSTIC FUNCTION
The TCM monitors the low brake solenoid valve circuit for open or short to power supply.
 
 
DESCRIPTIONS OF MONITOR METHODS
Owing to open circuit or short to power supply, less current than predetermined flows into the low brake solenoid valve drive circuit.
 
 
MONITOR EXECUTION
Continuous
 
 
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.
  • Voltage of battery: 16.5 volts or less.
Judgment Criteria
  • All the conditions listed below remain for 0.2 second.
    1. The low brake solenoid valve command current is 750 milliamperes or more.
    2. The low brake solenoid valve current, which the TCM monitors, is 200 milliamperes or less.
 
 
OBD-II DRIVE CYCLE PATTERN
Ignition switch: "ON" position (start the engine and keep it for five seconds or more)
 
 
PROBABLE CAUSES
  • Malfunction of the valve body assembly (Defective low brake solenoid valve)
  • Damaged wiring harness and connectors
  • Malfunction of TCM
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Check the following connector
  • CVT assembly connector
  • TCM connector
Check the terminals for a contact status problem and internal short circuit.
Is the check result normal?
Go to Step 2.
Repair the defective connector(s).
 
STEP 2. Check for open circuit or short to power supply in LBLS line between the CVT assembly connector and the TCM connector
Is the check result normal?
Go to Step 3.
Repair the wiring harness.
 
STEP 3. Low brake solenoid valve check
Refer to .
Is the check result normal?
Go to Step 4.
Replace the valve body assembly (Refer to ).
 
STEP 4. Using scan tool (M.U.T.-III), recheck the DTC.
Check again if the DTC is stored.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Carry out a test drive with the OBD-II drive cycle pattern.
(4) Recheck the DTC.
Is DTC P0974 stored?
Replace the TCM (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).