C2116

DTC C2116: Abnormality in power supply voltage in pump motor

CAUTION
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
^ When the hydraulic unit (integrated with ASC-ECU) is replaced, always perform the calibration of steering wheel sensor, G and yaw rate sensor, brake fluid pressure sensor, cut valve, and inlet valve.

CIRCUIT OPERATION
^ ASC-ECU contains the power supply circuit (terminal No. 1) for the motor. The pump motor is energized by the pump motor switch, which is incorporated in ASC-ECU.
^ The pump motor switch in ASC-ECU is turned off at all times unless during the motor solenoid valve check performed 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 diagnostic trouble code is set under the cases below.
^ The power supply voltage of pump motor, which is not in operation, is abnormally low for a prolonged period.
^ The voltage of pump motor, which is not in operation, is abnormally high for a prolonged period.

PROBABLE CAUSES

Current trouble
^ Fusible link malfunction
^ Damaged wiring harness and connectors
^ Abnormality in battery or generator
^ ASC-ECU malfunction

Past trouble
^ Perform the diagnosis with a particular emphasis on the wiring harness and connector failures in the ASC-ECU motor power supply circuit (A-05 ASC-ECU connector terminal No. 1) and in the ground circuit (A-05 ASC-ECU connector terminal No. 16 and No.47). For diagnosis procedures, refer to How to Treat Past Trouble.

DIAGNOSIS

Required Special Tools:
^ MB991958 Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827 M.U.T.-III USB Cable
^ MB991910 M.U.T.-III Main Harness
^ MB991997: ASC check harness

STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Using scan tool MB991958, diagnose the CAN bus lines.

Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. DTC recheck after repairing the CAN bus line

Q: Is DTC C2116 set?
YES: Go to Step 3.
NO: This diagnosis is complete.

STEP 3. Fusible link check: Check the fusible link No.26.

Q: Is the check result normal?
YES: Go to Step 4.
NO: Replace the fusible link No.26.

STEP 4. Battery check

Q: Is the battery in good condition?
YES: Go to Step 5.
NO: Charge or replace the battery.

STEP 5. Charging system check

Q: Is the charging system in good condition?
YES: Go to Step 6.
NO: Repair or replace the charging system component(s).

STEP 6. Voltage measurement at the A-05 ASC-ECU connector

1) Disconnect the connector, connect the ASC check harness (Special tool: MB991997) to the wiring harness-side connector, and measure the voltage at the special tool connector side.

NOTE: Do not connect the special tool to ASC-ECU.

2) Measure the resistance between the terminal No. 16 and the body ground as well as between the terminal No. 47 and the body ground.
OK: Continuity exists (2 C2 or less)

Q: Is the check result normal?
YES: Go to Step 10.
NO: Go to Step 9.

STEP 9. Connector check: A-05 ASC-ECU connector

Q: Is the check result normal?
YES: An open circuit may be present in the ground circuit. Repair the wiring harness between A-05 ASC-ECU connector terminal No. 16 and the ground as well as between A-05 ASC-ECU connector terminal No. 47 and the ground.
NO: Repair the defective connector.

STEP 10. Check whether the DTC is reset.
1) Erase the diagnostic trouble code.
2) Drive the vehicle at 12mph (20 km/h) or more.

NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph (20 km/h) or higher.

Q: Is DTC C2116 set?
YES: Replace the hydraulic unit (incorporates in ASC-ECU). Then go to Step 11.
NO: Intermittent malfunction.

STEP 11. Check whether the DTC is reset.
1) Erase the diagnostic trouble code.
2) Drive the vehicle at 12mph (20 km/h) or more.

NOTE: The ABS warning light does not turn OFF in some cases unless the vehicle runs at 12mph (20 km/h) or higher.

Q: Is DTC C2116 set?
YES: Return to Step 1.
NO: This diagnosis is complete.