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DTC P0847: Malfunction of the Primary Pressure Sensor (low input)
 
 
 
 
DIAGNOSTIC FUNCTION
The TCM determines that the system is defective when the primary pressure sensor output voltage is lower than a predetermined value.
 
 
DESCRIPTIONS OF MONITOR METHODS
The primary pressure sensor detects a voltage of 0.09 V or less for five seconds with the transmission fluid temperature more than -20°C (-4°F).
 
 
MONITOR EXECUTION
  • Voltage of battery: 10 volts or more.
  • Transmission fluid temperature: More than -20°C (-4°F).
 
 
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • P084A: Abnormality in primary pressure sensor function
  • P0970, P0971: Malfunction of primary pressure solenoid valve
Sensor (The sensor below is determined to be normal)
  • Primary pressure sensor
 
 
LOGIC FLOW CHARTS (Monitor Sequence)
 
 
DTC SET CONDITIONS
Check Conditions
  • Voltage of battery: 10 volts or more.
  • Transmission fluid temperature: More than -20°C (-4°F).
Judgment Criteria
  • The primary pressure sensor detects a voltage of 0.09 V or less for 5 seconds.
 
 
OBD-II DRIVE CYCLE PATTERN
Ignition switch: ON (start the engine and keep it for 10 seconds or more).
 
 
PROBABLE CAUSES
  • Malfunction of the valve body assembly (Faulty primary pressure sensor)
  • Damaged wiring harness and connectors
  • Malfunction of TCM
 
 
DIAGNOSIS
Required Special Tools
  • MB992006: Extra fine probe
STEP 1. Voltage measurement at TCM connector (PRPS terminal).
(1) Drive the vehicle until the engine is warmed up.
(2) Measure the TCM connector side by backprobing.
(3) Selector lever position: N.
(4) Engine: Idling.
(5) Measure the voltage between the TCM connector (PRPS terminal) and body ground.
Is the voltage approximately 0.09 V or less?
Go to Step 2.
Go to Step 8.
 
STEP 2. Voltage measurement at CVT assembly connector (SSPW terminal).
(1) Disconnect the CVT assembly connector connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between the CVT assembly connector (SSPW terminal) and body ground.
OK: approx. 5 V
Is the check result normal?
Go to Step 4.
: Go to Step 3.
 
STEP 3. Check for open circuit or short to ground in SSPW line between the CVT assembly connector and the CVT-ECU connector.
Is the check result normal?
Go to Step 9.
Repair the connector(s) or the wiring harness.
 
STEP 4. Check for open circuit or short to ground in PRPS line between the CVT assembly connector and the TCM connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or the wiring harness.
 
STEP 5. Check for open circuit in SGND line between the CVT assembly connector and the TCM connector.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or the wiring harness.
 
STEP 6. Check for open circuit or short to ground in signal line between the CVT assembly connector and the valve body harness connector (primary pressure sensor line).
Refer to .
Is the check result normal?
Go to Step 7.
Replace the valve body harness. (Refer to )
 
STEP 7. Check for open circuit or short to ground in power supply line between the CVT assembly connector and the valve body harness connector (sensor power supply line).
Refer to .
Is the check result normal?
Replace the valve body assembly. (Refer to )
Replace the valve body harness. (Refer to )
 
STEP 8. Voltage measurement at TCM connector (PRPS terminal).
(1) Drive the vehicle until the engine is warmed up.
(2) Measure the TCM connector side by backprobing.
(3) Selector lever position: N.
(4) Engine: Idling.
(5) Measure the voltage between the TCM connector (PRPS terminal) and body ground.
OK: approx. 0.90 - 0.92 V
Is the check result normal?
Go to Step 9.
Replace the valve body assembly. (Refer to )
 
STEP 9. 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 ).