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DTC C2116 Pump motor voltage low
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. 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.
 
 
OPERATION
  • ASC-ECU contains the power supply circuit (+BM terminal) for the pump motor. The pump motor is energized by the motor switch, which is incorporated in ASC-ECU.
  • The pump motor switch, which is incorporated in ASC-ECU, is always off unless the motor solenoid valve check is activated when the vehicle is started.
  • ASC-ECU activates the pump motor by turning on the ECU built-in pump motor switch.
 
 
 
DTC SET CONDITIONS
This DTCs will be set under the cases below:
  • When the power supply voltage of the pump motor, which is not in operation, is abnormally low for a prolonged period
  • When the power supply voltage of the pump motor, which is not in operation, is abnormally high for a prolonged period
 
 
 
TROUBLESHOOTING HINTS
Current trouble
  • Fusible link malfunction
  • Damaged wiring harness and connectors
  • Abnormality in battery or generator
  • ASC-ECU malfunction
Past trouble
  • Carry out diagnosis with particular emphasis on wiring harness and connector failures between the power supply circuit (+BM terminal) to the ASC-ECU motor and the ground circuit (GND1, GND2 terminal). For diagnostic procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/How to Treat Past Trouble ).
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Scan tool (M.U.T.-III) CAN bus diagnosis
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.
 
STEP 2. DTC recheck after resetting CAN bus lines
Is DTC No. C2116 set?
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 10.
 
STEP 4. Charging system check
Refer to GROUP 16 - - On-vehicle Service/Generator Output Line Voltage Drop Test .
Is the charging system in good condition?
Go to Step 5.
Repair or replace the charging system component(s). Then go to Step 10.
 
STEP 5. Fusible link check: Check the fusible link No.4 and SFB5.
Visually check for open circuit in the fusible link No.4 and SFB5.
Is the check result normal?
Go to Step 7.
Go to Step 6.
 
STEP 6. Resistance measurement at ASC-ECU connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Disconnect the fusible link No.4 or SFB5.
(3) Resistance between the +BM terminal and the body ground.
OK: No continuity
Is the check result normal?
Replace the fusible link No.4 or SFB5. Then go to Step 10.
The short circuit may be present in the power supply circuit. Repair the wiring harness between the ASC-ECU connector +BM terminal and the fusible link, and then replace the fusible link No.4 or SFB5. Then go to Step 10.
 
STEP 7. Voltage measurement at the ASC-ECU connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between the +BM terminal and the body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 8.
The open circuit may be present in the power supply circuit. Repair the wiring harness between the ASC-ECU connector +BM terminal and the fusible link. Then go to Step 10.
 
STEP 8. Resistance measurement at ASC-ECU connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Resistance between the GND1 terminal and the body ground, and between the GND2 terminal and the body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 9.
An open circuit may be present in the ground circuit. Repair the wiring harness between the ASC-ECU connector GND1 terminal and the body ground, and between the ASC-ECU connector GND2 terminal and the body ground. Then go to Step 10.
 
STEP 9. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No. C2116 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 10.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 10. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.
noteThe ABS warning light does not turn OFF in some cases unless the vehicle runs at 12 mph (20 km/h) or higher.
Is DTC No. C2116 set?
Return to Step 1.
This diagnosis is complete.