[23A] AUTOMATIC TRANSMISSION (FF) - - TROUBLESHOOTING <A/T> - DIAGNOSTIC TROUBLE CODE PROCEDURES <4G63, 4G64> - Code No.15: A/T Fluid Temperature Sensor SystemPRINT PAGE / INDEX / PRIOR / NEXT
DIAGNOSTIC TROUBLE CODE PROCEDURES <4G63, 4G64>
Code No.15: A/T Fluid Temperature Sensor System
OPERATION
  • The A/T fluid temperature sensor converts the automatic fluid temperature to voltage, and send the information to the engine-A/T-ECU.
  • The A/T fluid temperature rises, the resistance decreases. Thus, the sensor output voltage depends on the A/T fluid temperature. As the A/T fluid temperature rises, the output voltage will decrease.
DIAGNOSIS CODE SET CONDITIONS
If the A/T fluid temperature sensor output voltage is 4.5 volts or more after driving for 10 minutes or more, there is an open circuit in the A/T fluid temperature sensor and diagnosis code 15 is set.
PROBABLE CAUSES
  • Malfunction of the A/T fluid temperature sensor
  • Damaged harness wires and connectors
  • Malfunction of the engine-A/T-ECU
DIAGNOSIS PROCEDURE
STEP 1. MUT-II/III data list
Item 15: A/T fluid temperature sensor (Refer to Data List Table ).
Q: Is the check result normal?
YES:  Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Go to Step 2.
STEP 2. Measure the resistance at A/T control solenoid valve assembly connector B-21.
Disconnect the connector, and measure the resistance between terminal 1 and 2 at the sensor side.
OK:
  • 16.7 - 20.5 kΩ (at 0°C)
  • 7.3 - 8.9 kΩ (at 20°C)
  • 3.4 - 4.2 kΩ (at 40°C)
  • 1.9 - 2.2 kΩ (at 60°C)
  • 1.0 - 1.2 kΩ (at 80°C)
  • 0.57 - 0.69 kΩ (at 100°C)
Q: Is the check result normal?
YES:  Go to Step 3.
NO:  Replace the A/T fluid temperature sensor.
STEP 3. Connector check: B-21 A/T control solenoid valve assembly
Check for the contact with terminals.
Q: Is the check result normal?
YES:  Go to Step 4.
NO:  Repair the defective connector.
STEP 4. Measure the resistance at A/T control solenoid valve assembly connector B-21.
Disconnect the connector, and measure the resistance between terminal 2 and earth at the wiring harness side.
OK: 2 Ω or less
Q: Is the check result normal?
YES:  Go to Step 9.
NO:  Go to Step 5.
STEP 5. Measure the voltage at engine-A/T-ECU connector C-111.
  1. Connect A/T control solenoid valve assembly connector B-21.
  1. Turn the ignition switch to the ON position.
  1. Measure the voltage between engine-A/T-ECU connector C-111 terminal No.57 and earth.
    2. OK: 0.5 V or less
Q: Is the check result normal?
YES:  Go to Step 8.
NO:  Go to Step 6.
STEP 6. Connector check: C-111 engine-A/T-ECU connector
Check for the contact with terminals.
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Repair the defective connector.
STEP 7. MUT-II/III data list
Item 15: A/T fluid temperature sensor (Refer to Data List Table .)
Q: Is the check result normal?
YES:  Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Replace the engine-A/T-ECU.
STEP 8. Connector check: C-111 engine-A/T-ECU connector
Check for the contact with terminals.
Q: Is the check result normal?
YES:  Go to Step 14.
NO:  Repair
STEP 9. Measure the voltage at A/T control solenoid valve assembly connector B-21.
  1. Disconnect the connector, and measure the voltage between terminal 1 and earth at the wiring harness side.
  1. Turn the ignition switch to the ON position.
    2. OK: 4.5 - 4.9 V
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Go to Step 10.
STEP 10. Measure the voltage at engine-A/T-ECU connector C-109.
  1. Connect A/T control solenoid valve assembly connector B-21.
  1. Turn the ignition switch to the ON position.
  1. Measure the voltage between engine-A/T-ECU connector C-109 terminal No.124 and earth.
    2. OK:
    • 3.8 - 4.0 V (at 20°C)
    • 3.2 - 3.4 V (at 40°C)
    • 1.7 - 1.9 V (at 80°C)
Q: Is the check result normal?
YES:  Go to Step 12.
NO:  Go to Step 11.
STEP 11. Connector check: C-109 engine-A/T-ECU connector
Check for the contact with terminals.
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Repair the defective connector.
STEP 12. Connector check: C-109 engine-A/T-ECU connector
Check for the contact with terminals.
Q: Is the check result normal?
YES:  Go to Step 13.
NO:  Repair the defective connector.
STEP 13. Check the harness between A/T control solenoid valve assembly connector B-21 terminal No.1 and engine-A/T-ECU connector C-109 terminal No.124.
Check the output line for short-circuited or open circuit.
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Repair the wiring harness.
STEP 14. Check the harness between A/T control solenoid valve assembly connector B-21 terminal No.2 and engine-A/T-ECU connector C-111 terminal No.57.
Check the earth line for open circuit.
Q: Is the check result normal?
YES:  Go to Step 7.
NO:  Repair the wiring harness.
[23A] AUTOMATIC TRANSMISSION (FF) - - TROUBLESHOOTING <A/T> - DIAGNOSTIC TROUBLE CODE PROCEDURES <4G63, 4G64> - Code No.15: A/T Fluid Temperature Sensor SystemPRINT PAGE / INDEX / PRIOR / NEXT
©2004 Mitsubishi Motors Corporation