Wireless Control Module (WCM)
DTC B2101: IG SW Start POS.Circuit LowDTC B2102: IG SW Start POS.Circuit High
CAUTION:
- If DTC B2101 or B2102 is set, be sure to diagnose the CAN bus line.
- Before replacing the ECU, ensure that the communication circuit is normal.
WCM Communication Circuit:
DTC SET CONDITION
WCM sets DTC B2101 or B2102 when the actual state of the ignition switch and the ignition switch position information received from ETACS-ECU via CAN do not match.
TECHNICAL DESCRIPTION (COMMENT)
WCM determines that the abnormality is present, if it has detected discrepancy in the ignition switch level shown below ten consecutive times when WCM has received the CAN message (ignition switch position information) from ETACS-ECU with the ignition switch turned to the ON or START position.
B2101
- Status of ignition switch: OFF position
- Ignition switch position information from the ETACS-ECU: ON
B2102
- Status of ignition switch: ON position
- Ignition switch position information from the ETACS-ECU: OFF
TROUBLESHOOTING HINTS
- Malfunction of CAN bus line
- Malfunction of the WCM
- Malfunction of the ignition switch
- Damaged wiring harness and connectors
- 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 line.
CAUTION: To prevent damage to scan tool (MB991958), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (MB991958).
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES : Go to Step 2.
NO : Repair the CAN bus line.
STEP 2. Check ETACS-ECU connector C-317 and WCM connector C-07 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is ETACS-ECU connector C-317 and WCM connector C-07 in good condition?
YES : Go to Step 3.
NO : Repair the defective connector.
STEP 3. Check the wiring harness between WCM connector C-07 (terminal No.9) and the ETACS-ECU connector C-317 (terminal No.5) for open circuit.
1. Disconnect WCM connector C-07 and ETACS-ECU connector C-317, and check the wiring harness.
2. Check the wiring harness between WCM connector C-07 (terminal No.9) and ETACS-ECU connector C-317 (terminal No.5)
OK: Continuity exists (2 ohms or less)
Q: Is the wiring harness between WCM connector C-07 (terminal No.9) and the ETACS-ECU connector C-317 (terminal No.5) in good condition?
YES : Go to Step 4.
NO : Repair the wiring harness between WCM connector C-07 (terminal No.9) and ETACS-ECU connector C-317 (terminal No.5).
STEP 4. Using scan tool MB991958, check data list.
Use the ETACS-ECU data list to check the signals related to the ignition voltage.
1. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
Q: Does scan tool MB991958 display the item "IG voltage" as normal condition?
YES : Go to Step 5.
NO : Diagnose the ETACS-ECU (Refer to ETACS, Diagnosis). Diagnostic Trouble Code Descriptions
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set to the WCM.
1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
3. Check if DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Replace WCM and register the ID codes.
NO : The trouble can be an intermittent malfunction.