B2354
DTC B2353: Ignition Power Supply (Low Input)DTC B2354: Ignition Power Supply (High Input)
CAUTION: Before replacing the ECU, ensure that the input and output signal circuits are normal.
Ignition Switch (IG1) Input Circuit (Part 1):
Ignition Switch (IG1) Input Circuit (Part 2):
TROUBLE JUDGMENT
These DTCs are set when the ignition power supply voltage decreases to the specified value or less (DTC B2353) or increases to the specified value or more (DTC B2354). However, when the status returns to normal, the DTCs B2353 and B2354 are automatically erased.
TECHNICAL DESCRIPTION (COMMENT)
The power supply circuit or the ETACS-ECU may have a problem.
TROUBLESHOOTING HINTS
- The power supply circuit may be defective.
- The battery may be defective.
- The generator may be defective.
- The ETACS-ECU may be defective.
- The ignition switch 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. Using scan tool MB991958, check data list.
Check the ignition power supply voltage.
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)." Scan Tool Connecting
2. Check the ETACS data list.
- Turn the ignition switch to the "ON" position.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q : Do the scan tool MB991958 display the item "IG voltage" is normal condition?
YES : Go to Step 7.
NO : Go to Step 2.
STEP 2. Battery check
Refer to Battery Test. Testing and Inspection
Q : Is the battery in good condition?
YES : Go to Step 3.
NO : Charge or replace the battery.
STEP 3. Charging system check
Refer to Engine Electrical -Output Current Test.
Q : Is the charging system in good condition?
YES : Go to Step 4.
NO : Repair or replace the charging system component(s).
STEP 4. Check ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q : Is ETACS-ECU connector C-317 in good condition?
YES : Go to Step 5.
NO : Repair or replace the component(s). Refer to General (Electrical), Harness Connector Inspection.
STEP 5. Check the ignition switch (IG1) circuit to the ETACS-ECU. Measure the voltage at ETACS-ECU connector C-317.
1. Disconnect ETACS-ECU connector C-317 and measure the voltage available at the wiring harness side of the connector.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 6 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 7.
NO : Go to Step 6.
STEP 6. Check the wiring harness between ETACS-ECU connector C-317 (terminal 6) and the ignition switch (IG1).
Check the power supply line for open circuit and short circuit.
Q : Is the wiring harness between ETACS-ECU connector C-317 (terminal 6) and the ignition switch (IG1) 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 7. Recheck for diagnostic trouble.
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 (Refer to General (Body and Chassis), How to Cope with Intermittent Malfunction).