B210A

DTC B210A: +B power supply (low input)
DTC B210B: +B power supply (high input)

CAUTION:
Before replacing the ECU, ensure that the input and output signal circuits are normal.










TROUBLE JUDGMENT

The ETACS-ECU sets DTC B210A if the power supply fuse voltage decreases to the specified value or less, and sets DTC B210B if the power supply fuse voltage increases to the specified value or more. However, when the status returns to normal, the ETACS-ECU automatically erases DTCs B210A and B210B.

TECHNICAL DESCRIPTION (COMMENT)

The power supply fuse or the ETACS-ECU may have a problem.

TROUBLESHOOTING HINTS

- The power supply fuse may be defective.
- The ETACS-ECU may be defective.
- The battery may be defective.
- The generator may be defective.
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- 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. Power supply fuse check.

Q. Is the fuse in good condition?

YES Go to Step 3.
NO Go to Step 2.
STEP 2. Wiring harness check between C-307 ETACS-ECU connector and fuse No. 30.

(1)Disconnect ETACS-ECU connector C-307.

(2)Remove fuse No. 30.

(3)Check the continuity (short to ground) between C-307 ETACS-ECU connector terminal No. 2 and the ground.
OK: No continuity


Q. Is the check result normal?

YES Replace the fuse No.30.
NO A short circuit may be present in the power supply circuit. Check the wiring harness between ETACS-ECU connector C-307 terminal No. 2 and fuse No. 30, and repair if necessary and replace fuse No. 30.
STEP 3. Battery check

Refer to Battery Test.

Q. Is the battery in good condition?

YES Go to Step 4.
NO Charge or replace the battery.
STEP 4. Charging system check

Output Current Test.

Q. Is the charging system in good condition?

YES Go to Step 5.
NO Repair or replace the charging system component(s).
STEP 5. Check ETACS-ECU connector C-307 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is ETACS-ECU connector C-307 in good condition?

YES Go to Step 6.
NO Repair or replace the component(s). Harness Connector Inspection.
STEP 6. Check the battery power supply circuit to the ETACS-ECU. Measure the voltage at ETACS-ECU connector C-307.

(1)Disconnect ETACS-ECU connector C-307 and measure the voltage available at the wiring harness side of the connector.





(2)Measure the voltage between terminal 2 and ground.

- The voltage should measure approximately 12 volts (battery positive voltage).

Q. Is the measured voltage approximately 12 volts (battery positive voltage)?

YES Go to Step 8.

NO Go to Step 7.

STEP 7. Check the wiring harness between ETACS-ECU connector C-307 (terminal 2) and the fusible link (36).

Check the power supply line for open circuit.

Q. Is the wiring harness between ETACS-ECU connector C-307 (terminal 2) and the fusible link (36) in good condition?

YES No action is necessary and testing is complete.
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 8. Using scan tool MB991958, check data list.

Check the power supply fuse voltage.





(1)
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.

Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(2)Check the ETACS data list.

- Turn the ignition switch to the "LOCK" (OFF) position.





Q. Do the scan tool MB991958 display the item "voltage sensing of IOD Line" is normal condition?

YES Go to Step 9.

NO Replace the ETACS-ECU.

STEP 9. Recheck for diagnostic trouble code.

Check again if the DTC is set to the ETACS-ECU.

(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 the ETACS-ECU.
NO The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).