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DTC P1AAC: Current Sensor Signal Time Out
 
 
cautionWhenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
TROUBLE JUDGMENT
Check Conditions
  • The power supply mode of the electric motor switch is ON, or the main drive lithium-ion battery starts to be charged.
Judgment Criterion
  • The signal sent by the main drive lithium-ion battery current sensor through the CAN cannot be received.
 
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Not available
 
 
PROBABLE CAUSES
  • Harness and connector is failed.
  • CAN line harness damage or connector damage.
  • The main drive lithium-ion battery current sensor is failed.
  • The battery management unit (BMU) is failed.
 
 
 
 
DIAGNOSIS
Required Special Tools
  • MB991658: Test harness
STEP 1. Using scan tool (M.U.T.-IIISE), check whether the other DTC is set.
Check whether DTC No. P1AD3, P1AD4, P1AD5, P1AD6, P1AD7, P1AD9, P1ADA, P1ADB, P1ADC, P1ADD and U0112 are set at the same time.
Is the DTC set?
Go to Step 2.
Go to Step 5.
 
STEP 2. Measure the resistance at main drive lithium-ion battery connector.
(1) Disconnect the D-33 main drive lithium-ion battery connector, and measure at the wiring harness side.
(2) Check the resistance between the D-33 main drive lithium-ion battery connector (terminal No.3) and body ground.
OK: Continuity exists (2 Ω or less)
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Check of open circuit, short to ground or short to power supply in CNBL, CNBH line between main drive lithium-ion battery connector and BMU connector.
cautionWhen measuring the resistance, disconnect the negative auxiliary battery terminal.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Resistance measurement at BMU connector.
(1) Remove the BMU, and measure at the equipment side.
(2) Resistance between D-203 BMU connector terminal No.37 and 38.
OK: 120 ± 20 Ω
Is the check result normal?
Go to Step 7.
Replace the battery management unit (BMU) (Refer to ).
 
STEP 5. Using scan tool (M.U.T.-IIISE), check whether the other system DTC is set.
Check whether DTC No. U11B8 is set in the sub-battery management unit [BMU (SUB)].
Is the DTC set?
Go to Step 6.
Replace the battery management unit (BMU) (Refer to ).
 
STEP 6. Measure the voltage at main drive lithium-ion battery connector.
(1) Disconnect the D-33 main drive lithium-ion battery connector, and measure at the wiring harness side.
(2) Turn on the power supply mode of the electric motor switch.
(3) Check the voltage between the D-33 main drive lithium-ion battery connector (terminal No.2) and body ground.
OK: Battery voltage
Is the check result normal?
Go to Step 8.
Check the fuse or repair the fuse, connector(s) or wiring harness. If fuse is blown, refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - Inspection Service Points for a Blown Fuse .
 
STEP 7. Check whether the DTC is set again.
Recheck the DTC.
(1) Erase the DTC.
(2) Turn off the power supply mode of the electric motor switch.
(3) Turn on the power supply mode of the electric motor switch.
(4) Check the DTC.
Is the DTC set?
Unload main drive lithium-ion battery from the vehicle and repair or replace defective parts (the circuit and the terminal resistance can have an abnormality inside the main drive lithium-ion battery).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 8. Check of open circuit and damage circuit in line between main drive lithium-ion battery current sensor connector and joint connector.
(1) Remove the battery tray cover (Refer to ).
(2) Disconnect the I-02 joint connector (CAN7), I-15 joint connector (19), I-16 joint connector (18), I-18 joint connector (CAN8) and main drive lithium-ion battery current sensor connector, and measure at the wiring harness side.
(3) Check the line between the following terminals.
  • Between the main drive lithium-ion battery current sensor connector (IGCT terminal) and I-15 joint connector (19) (terminal No.2).
  • Between the main drive lithium-ion battery current sensor connector (GND terminal) and I-16 joint connector (18) (terminal No.3).
  • Between the main drive lithium-ion battery current sensor connector (CANH terminal) and I-18 joint connector (CAN8) (terminal No.19).
  • Between the main drive lithium-ion battery current sensor connector (CANL terminal) and I-18 joint connector (CAN8) (terminal No.8).
  • Between the I-18 joint connector (CAN8) (terminal No.9) and I-02 joint connector (CAN7) (terminal No.10).
  • Between the I-18 joint connector (CAN8) (terminal No.20) and I-02 joint connector (CAN7) (terminal No.21).
Is the check result normal?
Replace the main drive lithium-ion battery current sensor. Then, assemble the main drive lithium-ion battery assembly (Refer to ).
Repair the connector(s) or wiring harness. Then, assemble the main drive lithium-ion battery assembly (Refer to ).