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DTC B1731: PCM authentification timeout
 
 
caution
  • If DTC No.B1731 is stored in the ETACS-ECU, diagnose the CAN main bus line.
  • Whenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
TROUBLE JUDGMENT
If the ETACS-ECU cannot receive any signals from the engine control module, DTC No. B1731 will be set.
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
Connector(s) or wiring harness in the CAN bus lines between the ETACS-ECU and the engine control module, the power supply system to the engine control module, the engine control module itself, or the ETACS-ECU itself may be defective.
noteDTC No.B1731 is always set along with MFI system DTC No.U0167.
 
 
 
TROUBLESHOOTING HINTS
  • The engine control module may be defective
  • The ETACS-ECU may be defective
 
 
 
 
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 ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting). Repair the CAN bus line and go to Step 3.
 
STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
(1) Turn the ignition switch to the "LOCK" (OFF) position once, and then turn it to the ON position again.
(2) Check that DTC No.B1731 is not set as a current trouble.
Is DTC No.B1731 set?
Replace the ETACS-ECU. After registering the ID codes, go to Step 3.
The diagnosis is complete. If another DTC is stored, refer to DTC Chart .
 
STEP 3. Recheck for diagnostic trouble code.
Recheck if the DTC is stored.
(1) Turn the ignition switch to the "LOCK" (OFF) position once, and then turn it to the ON position again.
(2) Check that DTC No.B1731 is not set as a current trouble.
Is DTC No.B1731 set?
Replace the engine control module and resister the ID code.
The diagnosis is complete. If another DTC is stored, refer to DTC Chart .