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Code No. C1864: G/Yawrate SNS.power supply VOLT.
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be stored. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to and ).
 
 
OPERATION
The G and yaw rate sensor output signal is sent to the ASC-ECU.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITIONS
When the ignition switch is turned on, the G and yaw rate sensor monitors the power supply voltage. If abnormal voltage is detected, this diagnostic trouble code will be stored.
 
 
PROBABLE CAUSES
  • Battery failure
  • Charging system failed
  • Damaged harness wires and connectors
  • Malfunction of ASC-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use the scan tool MB991958 to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 3.
Repair the CAN bus line. (Refer to GROUP 54C - CAN Bus Trouble Symptom Chart .) On completion, go to Step 2.
 
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Is diagnostic trouble code No. C1864 stored?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Battery check
Refer to GROUP 54A - Battery Test .
Is the battery in good condition?
Go to Step 4.
Replace the battery. Then go to Step 5.
 
STEP 4. Check the charging system.
Refer to GROUP 16 - Charging System .
Is the charging system in good condition?
Go to Step 5.
Repair or replace the charging system component(s). Then go to Step 5.
 
STEP 5. Measure the resistance at the ASC-ECU connector.
(1) Check the connectors and the junction block.
(2) Disconnect the ASC-ECU connector.
(3) Measure the resistance between the IG1 terminal and body ground.
OK: No continuity
Is the check result normal?
Go to Step 6.
The power supply circuit may be short. Repair the wiring harness wires or connectors between the ACS-ECU connector IG1 terminal and the junction block. Then go to Step 8.
 
STEP 6. Measure the voltage at the ASC-ECU connector.
(1) Disconnect the ASC-ECU connector.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between the IG1 terminal and body ground.
OK: Battery voltage
Is the check result normal?
Go to Step 7.
The power supply circuit may be open. Repair the wiring harness wires or connectors between the ACS-ECU connector IG1 terminal and the junction block. Then go to Step 8.
 
STEP 7. Measure the resistance at the ASC-ECU connector.
(1) Disconnect the ASC-ECU connector.
(2) Measure the resistance between the GND1 terminal and body ground as well as between the GND2 terminal and body ground.
OK: Continuity exists (2 Ω or less).
Is the check result normal?
Go to Step 8.
The ground circuit may be open. Repair the wiring harness wires or connectors between the ACS-ECU connector GND1 terminal and the fusible links as well as between the GND2 terminal and the fusible links. Then go to Step 8.
 
STEP 8. Check whether the diagnostic trouble code is stored again.
Check again if the diagnostic trouble code is stored.
(1) Erase the stored diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF)
(3) Ignition switch: "ON"
Is diagnostic trouble code No. C1864 stored?
Replace the hydraulic unit (integrated with ASC-ECU). (Refer to .)
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).