Code No.B1731
Engine-ECU communication timeout
| caution |
- When the diagnosis
code No. B1731 is set, be sure to diagnose the CAN bus line.
- When replacing the ECU, always check that the communication circuit is normal.
|
DIAGNOSTIC FUNCTION
KOS-ECU checks that the engine-ECU data has been received via the CAN bus lines, and if
not, sets the diagnosis code No. B1731.
JUDGEMENT CRITERIA
If no data [ETACS transmits engine random number data to KOS-ECU via the CAN
bus lines] is received from the engine ECU via the CAN bus lines when the ignition
switch is turned to ON position, it is judged as abnormal.
PROBABLE CAUSES
- Malfunction of CAN bus line
- Malfunction of KOS-ECU
- Malfunction of engine-ECU
- Damaged wiring harness and connectors
- Malfunction of ETACS-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting 
).
On completion, go to Step 2.
STEP 2. M.U.T.-III other system diagnosis code
Check if any diagnosis code is set to the engine-ECU.
Q.
Is the diagnosis code set?
Perform troubleshooting for the engine (Refer to GROUP 13A - Troubleshooting <1500,
1600>, GROUP 13B - Troubleshooting <1800,
2000-Petrol>, GROUP 13E - Troubleshooting <RALLIART> or
GROUP 13C - Troubleshooting <1800-Diesel>).
Go to Step 3.
STEP 3. M.U.T.-III other system diagnosis code
Check if diagnosis code No.U0100 is set to ETACS-ECU.
Q.
Is the diagnosis code set?
Go to Step 5.
Go to Step 4.
STEP 4. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set to KOS-ECU.
|
|
(1)Turn the ignition switch from the LOCK (OFF) position to the ON position.
|
|
|
(2)Check if the diagnosis code is set.
|
Q.
Is the diagnosis code set?
Replace KOS-ECU and register the ID codes (Refer to ).
Then go to Step 6.
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
STEP 5. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set to KOS-ECU.
|
|
(1)Turn the ignition switch from the LOCK (OFF) position to the ON position.
|
|
|
(2)Check if the diagnosis code is set.
|
Q.
Is the diagnosis code set?
Replace the engine-ECU and register the chassis number and key codes [Refer
to GROUP 00 - How to Perform Chassis Number (Chassis No.) Writing ].
The diagnosis is complete.
STEP 6. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set to KOS-ECU.
|
|
(1)Turn the ignition switch from the LOCK (OFF) position to the ON position.
|
|
|
(2)Check if the diagnosis code is set.
|
Q.
Is the diagnosis code set?
Replace the ETACS-ECU.
The diagnosis is complete.
faq.Lancer-Club.ru