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Inspection Procedure 1: Cannot communicate with KOS&OSS-ECU using the scan tool
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
KOS&OSS-ECU is communicating with scan tool via CAN. Therefore, communication error of KOS&OSS-ECU is suspected.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the power supply and the ground of KOS&OSS-ECU
  • Malfunction of CAN bus line
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the "OFF" position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III) [Refer to "How to connect scan tool (M.U.T.-III) "].
(2) Turn the power supply mode of the engine switch to "ON".
(3) Diagnose the CAN bus line.
(4) Turn the power supply mode of the engine switch to "OFF".
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Check the power supply circuit and the ground circuit to KOS&OSS-ECU.
Refer to Inspection Procedure 3 "Abnormality in KOS&OSS-ECU power supply and ground circuits" .
Is the power supply circuit and the ground circuit to KOS-ECU in good condition ?
Go to Step 3.
Repair the power supply circuit and the ground circuit to KOS&OSS-ECU.
 
STEP 3. Retest the system
Check if scan tool can communicate with KOS&OSS-ECU.
Does the scan tool cannot with KOS-ECU?
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace KOS&OSS-ECU and register the ID codes (Refer to ).