Keyless Operation System (KOS)

DTC C1901: Vehicle speed information abnormality

CAUTION:
If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines CAN Bus Diagnostics Chart).

DTC SET CONDITION

KOS-ECU receives the wheel speed information from ASC-ECU via the CAN-bus line. Although KOS-ECU receives the information that the wheel is not currently rotated from ASC-ECU, if the TPMS transmitter sends the information that the wheel is rotated, this code is set.

TROUBLESHOOTING HINTS

The most likely causes for this DTC to set are:

- Damaged wiring harness and connector
- Malfunction of TPMS transmitter
- Malfunction of KOS-ECU
- Malfunction of ASC-ECU
- Malfunction of ETACS-ECU

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A


STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.

Use scan tool to diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair the CAN bus lines Controller Area Network (CAN)). On completion, go to Step 2.
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines

(1)Turn the ignition switch to the "LOCK" (OFF) position.

(2)Turn the ignition switch to the "ON" position.

(3)Check if the DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC C1901 set?

YES Go to Step 3.
NO The procedure is complete.
STEP 3. Check for other diagnostic trouble code.

Check if the diagnostic trouble code is set from ASC-ECU Active Stability Control System (ASC)).

Q. Is the check result normal?

YES Go to Step 4.
NO Carry out the troubleshooting for ASC-ECU Active Stability Control System (ASC)). Then go to Step 6.
STEP 4. Check for other diagnostic trouble code.

Check if the diagnostic trouble code is set from ETACS-ECU Electronic Time and Alarm Control System (ETACS)).

Q. Is the check result normal?

YES Go to Step 5.
NO Troubleshoot the set DTC Electronic Time and Alarm Control System (ETACS)). Then go to Step 6.
STEP 5. Check the TPMS transmitter acceleration.

Check the acceleration value of each TPMS transmitter by the air pressure of data list (Refer to Data List Reference Table).

OK:

Acceleration value: 5G or less


Q. Is the check result OK?

YES Replace the KOS-ECU and register ID codes (Refer to ID Code Registration Judgment Table). Then go to Step 6.
NO Replace the TPMS transmitter and register ID codes (Refer to ID Code Registration Judgment Table). Then go to Step 6.
STEP 6. Recheck for diagnostic trouble code.

(1)Turn the ignition switch to the "LOCK" (OFF) position.

(2)Turn the ignition switch to the "ON" position.

(3)Check if the DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC C1901 set?

YES Start over at Step 1.
NO The procedure is complete.