Code No.31: ASTC-ECU power supply system (open circuit or short circuit)








OPERATION



DIAGNOSIS CODE SET CONDITIONS



PROBABLE CAUSES



  • Damaged wiring harness or connector
  • Malfunction of the ASTC-ECU

DIAGNOSIS

STEP 1. Check ASTC-ECU connector D-233 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is the check result normal?
Go to Step 2.
Repair it. Then go to Step 6.

STEP 2. Check the power supply circuit at ASTC-ECU harness connector D-233.
(1)Disconnect ASTC-ECU connector D-233 and measure at the harness connector (harness side).
(2)Start the engine.
(3)Measure the voltage between terminal 9 and body earth.
OK: Approx. 12 volts (battery positive voltage)

Q. Is battery positive voltage (approx. 12 volts) present?
Go to Step 5.
Go to Step 3.

STEP 3. Check intermediate connector D-231 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is the check result normal?
Go to Step 4.
Repair or replace it. Then go to Step 6.

STEP 4. Check the harness wires between ASTC-ECU connector D-233 (terminal 9) and multi-purpose fuse number 22 (fuse box).

Q. Is the check result normal?
Go to Step 6.
Repair or replace it. Then go to Step 6.

STEP 5. Recheck for diagnosis code.
(1)Erase the diagnosis code.
(2)Recheck for diagnosis code.

Q. Is code No.31 set?
Replace the ASTC-ECU (Refer to GROUP 35C, ASTC-ECU ). Then go to Step 6.
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .

STEP 6. Recheck for diagnosis code.
(1)Erase the diagnosis code.
(2)Recheck for diagnosis code.

Q. Is code No.31 set?
Start over at Step 1.
The procedure is complete.