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DTC B2353: Ignition power supply (low)
DTC B2354: Ignition power supply (high)
 
 
cautionBefore replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
DTC SET CONDITION
These DTC are set when the IG voltage decreases to the specified value or less (DTC No. B2353) or increases to the specified value or more (DTC No. B2354). However, when the status returns to normal, DTC Nos. 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 12V starter battery may be defective.
  • The generator may be defective.
  • The electric motor switch may be defective.
  • The ETACS-ECU may be defective.
  • The OSS-ECU 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
STEP 1. Using scan tool (M.U.T.-IIISE), check data list.
Check the IG voltage.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan Tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Check the ETACS data list.
  • Turn the electric motor switch to the "OFF" position.
 
Item No.Item nameNormal condition
253Voltage sensing of IOD LineBattery positive voltage
OK: Normal condition is displayed.
Is the check result normal?
Go to Step 6.
Go to Step 2.
 
STEP 2. 12V starter battery check
Refer to .
Is the 12V starter battery in good condition?
Go to Step 3.
Charge or replace the 12V starter battery.
 
STEP 3. Charging system check
Refer to GROUP 54Da - PHEV-ECU, Symptom Procedures .
Is the charging system in good condition?
Go to Step 4.
Repair or replace the charging system component(s).
 
STEP 4. Voltage measurement at ETACS-ECU connector (IG1 terminal)
(1) Measure by backprobing without disconnecting the connector.
(2) Press the electric motor switch to turn on the power supply mode.
(3) Check the voltage between the ETACS-ECU connector (IG1 terminal) and ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check of short to power supply, short to OSS-ECU (IG1) connector and ETACS-ECU connector
Is the check result normal?
Refer to GROUP 42B - OSS-ECU, Symptom Procedures .
Repair the connector(s) or wiring harness.
 
STEP 6. Recheck for DTC.
Check again if the DTC is set in the ETACS-ECU.
(1) Erase the DTC.
(2) Press the electric motor switch to turn the power supply mode from "OFF" to "ON."
(3) Check if DTC is set.
Is the DTC set?
Replace the ETACS-ECU.
The trouble can be an intermittent malfunction (GROUP 00 - How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).