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DTC B1731: PCM authentification timeout
 
 
caution
  • When DTC B1731 is set, be sure to diagnose the CAN bus line.
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DTC SET CONDITION
If the necessary data cannot be received from engine control module via CAN bus line during the engine starting certification with engine control module, KOS&OSS-ECU determines that a problem has occurred, and sets DTC B1731. At the same time, KOS&OSS-ECU displays the immobilizer certification system inspection warning to the combination meter.
 
 
TECHNICAL DESCRIPTION (COMMENT)
Check Conditions
  • At engine starting certification
Judgment Criterion
  • At the engine starting certification with engine control module, necessary data cannot be received from engine control module via CAN bus line.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the CAN bus line
  • Malfunction of engine control module
  • Malfunction of KOS&OSS-ECU
 
 
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. Using scan tool (M.U.T.-III), read the other system diagnostic trouble code.
Check again if the DTC is set in the engine control module.
(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) Erase the DTC.
(3) Turn the power supply mode of the engine switch to "ON".
(4) Check if DTC is set.
(5) Turn the power supply mode of the engine switch to "OFF".
Is the DTC set?
Perform troubleshooting for the engine control module (Refer to GROUP 13A, Troubleshooting ). On completion, go to Step 3.
Go to Step 3.
 
STEP 3. Recheck for diagnostic trouble code.
(1) Turn the engine switch "OFF" and "ON" several times without depressing the brake pedal (Perform quickly within approximately five seconds).
(2) Erase the DTC.
(3) Turn the power supply mode of the engine switch from "OFF" to "ON".
(4) Check if DTC is set.
Is the DTC set?
Replace the KOS&OSS-ECU and register the VIN (Refer to ). On completion, go to Step 4.
Intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
 
STEP 4. Recheck for diagnostic trouble code.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from "OFF" to "ON".
(3) Check if DTC is set.
Is the DTC set?
Replace the engine control module.
Intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).