Code No.P1790 Back up line system








OPERATION



DIAGNOSIS CODE SET CONDITION



PROBABLE CAUSES



  • Damaged harness wires and connectors
  • Malfunction of the A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Measure the voltage at A/T-ECU connector C-12.
(1)Measure the voltage between A/T-ECU connector C-12 terminal No.38 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4.
Go to Step 2.

STEP 2. Connectors check: A-115 intermediate connector, C-12 A/T-ECU connector.
Check for the contact with terminals.

Q. Is the check result normal?
Go to Step 3.
Repair the defective connector.

STEP 3. Check the harness between A/T-ECU connector C-12 terminal No.38 and fusible link (23).
Check the power supply line for short or open circuit.

Q. Is the check result normal?
Go to Step 5.
Repair the wiring harness.

STEP 4. Connector check: C-12 A/T-ECU connector.
Check for the contact with terminals.

Q. Is the check result normal?
Go to Step 5.
Repair the defective connector.

STEP 5. Replace the A/T-ECU and then recheck the diagnosis code.
(1)Replace the A/T-ECU.
(2)Test drive the vehicle.
(3)Check the diagnosis code.

Q. Is the diagnosis code set?
Go to Step 1.
The inspection is complete.