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DTC P0843: Malfunction of the Secondary Pressure Sensor (High Voltage)
 
 
 
 
DIAGNOSTIC FUNCTION
The TCM determines that the system is defective when the secondary pressure sensor output voltage is higher than a predetermined value.
 
 
DESCRIPTIONS OF MONITOR METHODS
The status with the fluid temperature of -20°C (-4°F) or more and with the secondary pressure sensor voltage of 4.70 volts or more continues for five seconds.
 
 
MONITOR EXECUTION
Transmission fluid temperature: -20°C (-4°F) 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
  • Voltage of battery: 16.5 volts or less
  • Transmission fluid temperature: -20°C (-4°F) or more
Judgment Criteria
  • The secondary pressure sensor output voltage is 4.70 volts or more for five seconds.
 
 
OBD-II DRIVE CYCLE PATTERN
Ignition switch: "ON" position (start the engine and keep it for 10 seconds or more)
 
 
PROBABLE CAUSES
  • Malfunction of the valve body assembly (Defective secondary pressure sensor)
  • 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.
 
STEP 2. Check for open circuit in SGND 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. Check for short to power supply in LPRS line between the CVT assembly connector and the TCM connector.
Is the check result normal?
Go to Step 4.
Repair the wiring harness.
 
STEP 4. Voltage measurement at TCM connector (LPRS terminal).
(1) Connect the CVT assembly connector and the TCM connector.
(2) Drive the vehicle until the engine is warmed up.
(3) Measure the TCM connector side by backprobing.
(4) Transmission range: "P" range
(5) Engine: Idling
(6) Measure the voltage between the TCM connector (LPRS terminal) and (SGND terminal).
OK: approximately 0.84 volt
Is the check result normal?
Go to Step 5.
Replace the valve body assembly (Refer to ).
 
STEP 5. 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 P0843 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 ).