Code No. C1902: Reset fail (warning threshold)

caution

If diagnosis code No. C1902 is set, diagnose the CAN bus lines.
When replacing the ECU, always check that the communication circuit is normal.

DIAGNOSIS FUNCTION

When a tyre inflation pressure warning threshold value cannot be reset due to a timeout (10 minutes or more have passed in total at 35 km/h or more), the ETACS-ECU <Vehicles without KOS> or KOS-ECU will set a diagnosis code.

PROBABLE CAUSES

Malfunction of CAN bus line
Damaged wiring harness and connector
Malfunction of TPMS transmitter
Malfunction of ETACS-ECU <Vehicles without KOS> or KOS-ECU
ID code registration failed
Registered IDs unmatched
Effective ID set unmatched

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 lines (Refer to GROUP 54C - Troubleshooting). On completion, go to Step 2.

STEP 2. Check whether the diagnosis code is set again.

(1)Turn the ignition switch (engine starting switch) from the "LOCK" (OFF) to "ON" position.

(2)Check if the diagnosis code is set.

Q. Is the diagnosis code set?

	Go to Step 3.

	The procedure is complete.

STEP 3. Check whether the diagnosis code is set.

Q. Are all of Code Nos. C1911, C1921, C1931 and C1941 set?

	Press the multi-information display switch to toggle tyre ID sets. Then perform TPMS TRANSMITTER CHECK. (Toggling the tyre ID set will trigger the reset function automatically. Then the TPMS warning lamp will start flashing slowly. Furthermore, C1911, C1921, C1931 and C1941 will be set as "stored".) Then go to Step 4.

	Go to Step 7.

STEP 4. Check the tyre IDs for the TPMS transmitters.

Could all the tyre IDs for the TPMS transmitters be confirmed?

Q. Is the check result normal?

	Adjust the tyre inflation pressure to the recommended value. Then road test for a while to complete the reset function. Then go to Step 6.

	Go to Step 5.

STEP 5. Check the tyre IDs for the TPMS transmitters.

Could any of the tyre IDs for the TPMS transmitters be confirmed?

Q. Is the check result normal?

	Register the applicable IDs to the ECU as the active tyre ID set (Refer to ).Then go to Step 8.

	Register applicable IDs to the ECU as the previous ID set (Refer to ).Then go to Step 8.

STEP 6. Check the reset function.

Check whether the reset function has been completed normally.

Q. Has the reset function been completed normally?

	The procedure is complete (The incorrect tyre ID set has been activated, and this is not a malfunction.)

	If the reset function has not been completed after 10-minute road test, register applicable IDs as the active tyre ID set (Refer to ).Then go to Step 8.

STEP 7. Check for TPMS transmitter.

Identify the TPMS transmitter which the diagnosis code is set by TPMS transmitter check (Refer to

note

The TPMS transmitter which cannot be checked may be faulty or the ID code may not be registered, thus do not replace it, but register the ID code. If the transmitter is faulty, it is replaced in the ID code registration process.

Q. Are there any TPMS transmitters which are identified?

	Among the checked TPMS transmitters, replace the TPMS transmitters to which the diagnosis code is set. Then register the ID codes (Refer to ). Then go to Step 8.

	Even when no transmitter is checked, register the ID codes (Refer to ). Then go to Step 8.

STEP 8. Recheck for diagnosis code.

(1)Turn the ignition switch (engine starting switch) from the "LOCK" (OFF) to "ON" position.

(2)Check if the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the KOS-ECU (Refer to GROUP 42B - KOS-ECU ) <Vehicles without KOS> or ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ) and register the ID codes. Then start over at Step 1.

	The procedure is complete.