B2470

DTC B2468: Microphone Input Short To BATT
DTC B2470: Microphone Input Short To Ground

CAUTION: Before replacing the module, ensure that the communication circuit is normal.

Hands Free Cellular Phone System Circuit:

JUDGMENT CRITERIA
When the hands free module judges that the connection with microphone unit is abnormal for 5 seconds or more, it stores diagnostic trouble code B2468 or B2470.

PROBABLE CAUSES
- The hands free module may be defective.
- The microphone unit may be defective.
- Damaged harness wires and connectors


DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles 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.

Use scan tool MB991958 to diagnose the CAN bus lines.

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 (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line.

Q: Is the check result normal?

YES : Go to Step 2.

NO : Repair the CAN bus line.

STEP 2. Check microphone unit connector D-04 and hands free module connector C-11 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are microphone unit connector D-04 and hands free module connector C-11 in good condition?

YES : Go to Step 3.

NO : Repair the defective connector.

STEP 3. Check the wiring harness between microphone unit connector D-04 (terminal 1, 2) and hands free module connector C-11 (terminal 23, 24).

- Check the communication lines for open circuit and short circuit.

NOTE: Also check intermediate connector C-133 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-133 is damaged, repair or replace the connector.

Q: Is the wiring harness between microphone unit connector D-04 (terminal 1, 2) and hands free module connector C-11 (terminal 23, 24) in good condition?

YES : Go to Step 4.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

STEP 4. Recheck for diagnostic trouble code.

Check again if the DTC is set to the hands free module
1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
3. Check if DTC is set.

Q: Is the DTC set?

YES : Go to Step 5.

NO : The trouble can be an intermittent malfunction.

STEP 5. Temporarily replace the microphone unit, and check whether the diagnostic trouble code.

1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
3. Check if DTC.

Q: Is the DTC set?

YES : Replace the hands free module.

NO : Replace the microphone unit.