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DTC No. P0AF9-00 CC Diagnosis - Uneven Cell Voltage
 
 
 
 
MONITOR EXECUTION
Once per driving cycle (During the BMU activation)
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • BMU monitor
  • Drive battery voltage sensor circuit monitor
Sensor (The sensor below is determined to be normal)
  • Drive battery voltage sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Condition
  • The BMU power supply voltage is more than 7.578 volts.
  • The soaking time is 360 seconds or more.
Judgment Criterion
  • The value subtracting the minimum cell voltage from the maximum cell voltage is specified value or more.
 
 
OBD-II DRIVE CYCLE PATTERN
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the cell voltage wiring harness
  • Malfunction of the drive battery (battery module)
  • Malfunction of the bus bar
  • Malfunction of the BMU
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.Check of other DTC
Check whether the BMU and BMU2 set the following DTC.
  • DTC No. P0A1F-00 ECU Internal Failure
Is the DTC set?
Troubleshoot the set DTC (Refer to DIAGNOSTIC TROUBLE CODE CHART). Then,
 
2.Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to OBD-II Drive Cycle OBD-II DRIVE CYCLE.
(2) Check the DTC.
Is the DTC set?
The trouble can be an intermittent malfunction (Refer to General Information - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).
 
3.M.U.T.-IIISE freeze frame data check
Using the M.U.T.-IIISE, check the following BMU freeze frame data.
  • Item Nos. 220 to 1170: Cell Voltage1 to 96
Record the cell numbers show the minimum cell voltage and maximum cell voltage. Then,
 
4.Check the looseness or foreign material attached on the bus bar
(1) Disassemble the drive battery (Refer to SERVICE PROCEDURE).
(2) Check that there is no looseness or foreign material attached on the bus bar of the battery modules which the recorded cell numbers belong to.
Is the check result normal?
Repair it. Then,
 
5.Cell voltage harness check
Check the cell voltage harness of the battery modules which the recorded cell numbers belong to (Refer to CELL VOLTAGE HARNESS CHECK).
Is the check result normal?
Replace the cell voltage harness (Refer to SERVICE PROCEDURE). Then,
 
6.Module check
Check the battery modules which the recorded cell numbers belong to (Refer to BATTERY MODULE CHECK).
Is the check result normal?
Replace the BMU (Refer to BATTERY MANAGEMENT UNIT (BMU) REMOVAL AND INSTALLATION). Then,
Replace the failed module (Refer to SERVICE PROCEDURE). Then,
 
7.Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to OBD-II Drive Cycle OBD-II DRIVE CYCLE.
(2) Check the DTC.
Is the DTC set?
Retry the troubleshooting.
The procedure is complete.