Wireless Control Module (WCM)
DTC C1912: Tire Inflation Pressure Warning 1DTC C1922: Tire Inflation Pressure Warning 2
DTC C1932: Tire Inflation Pressure Warning 3
DTC C1942: Tire Inflation Pressure Warning 4
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 (Refer to Trouble code diagnosis). Can Bus Diagnostics Table
DTC SET CONDITION
When the tire pressure included in the signal from the TPMS transmitter is less than the specified value, WCM sets this code.
TROUBLESHOOTING HINTS
The most likely causes for this DTC to set are:
- Drop of tire pressure
- Loose TPMS transmitter mounting nut
- Flat tire
- TPMS transmitter malfunction
- WCM malfunction
- CAN-bus line malfunction
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. On completion, go to Step 2.
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Q: Is DTC C1912, C1922, C1932 or C1942 set?
YES : Go to Step 3.
NO : The procedure is complete.
STEP 3. Tire check
Check that there is no abnormality for the items below.
- Flat tire
- Cracked tire
- Air leak from valve
- Loose TPMS transmitter mounting nut.
Q: Is the check result normal?
YES : Go to Step 4.
NO : Repair or replace it. Then go to Step 4.
STEP 4. Diagnostic trouble code check
1. Turn the ignition switch to the "ON" position, and adjust the pressure to the recommended tire pressure.
2. Check if the DTC is set.
Q: Is DTC C1912, C1922, C1932 or C1942 set?
YES : Go to Step 5.
NO : The procedure is complete.
STEP 5. Diagnostic trouble code check
1. Drive the vehicle for five minutes.
NOTE: Even within 5 minutes, if the TPMS warning light goes out, finish the driving and perform the operation (2).
2. Check if the DTC is set.
Q: Is DTC C1912, C1922, C1932 or C1942 set?
YES : Go to Step 6.
NO : The procedure is complete.
STEP 6. Tire pressure check by scan tool
1. Perform the transmitter check using the scan tool, ID Codes Registration Procedure and check the tire pressure values of all the wheels.
2. Check the tire pressure of all the wheels using the tire pressure gauge.
3. Compare the measured value (1) with (2).
OK: 20 kPa (2.9 psi) or less
NOTE: Do not replace the TPMS transmitter which cannot be checked.
Q: Is the check result OK?
YES : Replace the WCM and register the ID codes. Then go to Step 9.
NO : Go to Step 7.
STEP 7. Tire pressure check by scan tool
1. Perform the transmitter check using the scan tool, ID Codes Registration Procedure and check the tire pressure values of all the wheels.
2. Check the tire pressure of all the wheels using the tire pressure gauge.
3. Compare the measured value (1) with (2).
OK: 20 kPa (2.9 psi) or less
Q: Is the check result OK?
YES : Replace the WCM and register the ID codes. Then go to Step 9.
NO : Replace the TPMS transmitter and register the ID codes. Then go to Step 8.
STEP 8. 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 C1912, C1922, C1932 or C1942 set?
YES : Replace the WCM and register the ID codes. Then go to Step 9.
NO : The procedure is complete.
STEP 9. 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 C1912, C1922, C1932 or C1942 set?
YES : Start over at Step 1.
NO : The procedure is complete.