B212D
DTC B212C: Open Circuit to IG1 Power Supply (Fuse No.12 Circuit)DTC B212D: Open Circuit to IG1 Power Supply (Fuse No.18 Circuit)
IG1 Power Supply Circuit:
CAUTION: If DTC B212C (Fuse No.12) or B212D (Fuse No.18 is set in the SRS-ECU, always diagnose the CAN main bus lines.
CIRCUIT OPERATION
- The SRS-ECU is powered from the ignition switch (IG1).
- The SRS-ECU power is supplied from two circuits. Even if one circuit is shut off, the air bag can inflate.
DTC SET CONDITIONS
This DTC is set if the voltage between the IG1 terminals (fuse No.12 circuit or fuse No.18 circuit) and ground is lower than a predetermined value for a continuous period of five seconds or more.
TROUBLESHOOTING HINTS
- Open circuit to power supply circuit
- Damaged wiring harnesses or connectors
- Malfunction of the SRS-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 (Vehicles with CAN communication system)
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. Refer to "How to connect the scan tool". Scan Tool Connecting
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 (Refer to Controller area network Diagnosis).
STEP 2. Using scan tool MB991958, diagnose the ETACS.
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. Refer to "How to connect the scan tool". Scan Tool Connecting
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 set?
YES : Diagnose the ETACS (Refer to Interior ETACS, Diagnosis).
NO : Go to Step 3).
STEP 3. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Go to Step 4.
NO : There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to general (body and chassis) How to Cope with Intermittent Malfunction).
STEP 4. Check the harness for open circuit between SRS-ECU connector C-30 (terminal No.61 and 62) and the ETACS-ECU connector C-313 (terminal No.4 and 2).
1. Disconnect SRS-ECU connector C-30.
2. While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-30 SRS-ECU connector.
3. Disconnect the ETACS-ECU connector C-313.
4. Check for continuity between the following terminals. It should be less than 2 ohms.
- SRS-ECU connector C-30 (terminal No.62) and the ETACS-ECU connector C-313 (terminal No.2)
- SRS-ECU connector C-30 (terminal No.61) and the ETACS-ECU connector C-313 (terminal No.4)
Q: Does continuity exist?
YES : Go to Step 5.
NO : Replace the harness wire between SRS-ECU connector C-30 and the ETACS-ECU connector C-313.
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Erase the DTC.
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 DTC B212C
YES : Return to Step 1.
NO : The procedure is complete.