C1514
DTC C1514 Torque sensor power supply too 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 Scan Tool Testing and Procedures ).
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
OPERATION
- Power is supplied to the torque sensor from the electric power steering-ECU.
FUNCTION
- To output the voltage based on the input torque from the torque sensor to the electric power steering-ECU, the voltage is supplied to the torque sensor.
TROUBLE JUDGMENT
Check Conditions
- Torque sensor power supply ON
Judgment Criterion
- The torque sensor power supply voltage is less than 2.5 V.
- The torque sensor power supply monitor voltage does not meet a predetermined voltage stored in the microcomputer, and the microcomputer determines that there is a problem in the torque sensor power supply voltage.
Fail Safe, Back Up Function
- The electric power steering-ECU stops the motor control and illuminates the electric power steering warning display, then sets the DTC No. C1514.
PROBABLE CAUSES
- Malfunction of CAN bus line
- Defective torque sensor of the steering gear and linkage assembly
- Defective harness wire(s) or connector(s)
- Short or open circuit between the electric power steering-ECU and the torque sensor or loose connector contact
- Open circuit between the body ground and the electric power steering-ECU or loose connector contact
- Malfunction of the electric power steering-ECU
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 A (Vehicles with CAN communication system)
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use scan tool to diagnose the CAN bus lines.
Q. Is the check result normal?
YES Go to Step 3.
NO Repair the CAN bus lines CAN Bus Diagnostics Chart).On completion, go to Step 2.
STEP 2. DTC recheck after resetting CAN bus lines
(1)Erase the DTC.
(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the DTC is set.
Q. Is the DTC C1514 set?
YES Go to Step 3.
NO This diagnosis is complete.
STEP 3. Check the following connector.
Check the connectors below for improper engagement, terminal damage or terminal drawn in the connector case.
- C-140 and C-141-1 electric power steering-ECU connector
- Body ground point
- Torque sensor intermediate connector of the wiring harness for steering gear box & linkage assembly (connection and appearance checks only)
Q. Is the connectors and terminals in good condition?
YES Go to Step 4.
NO Replace the steering gear and linkage assembly (Refer to Electrical Power Steering System (EPS)).
Then go to Step 8.
STEP 4. Wiring harness check
(1)Check the wiring harness between the C-141-1 electric power steering-ECU connector terminals No.30 or No.31 and the torque sensor for damage or other problem .
(2)Check the wiring harness between the C-140 electric power steering-ECU connector terminal No.12 and the body ground point for damage or other problem .
Q. Is the wiring harness in good condition?
YES Go to Step 5.
NO Replace the steering gear and linkage assembly (Refer to Electrical Power Steering System (EPS)).
Then go to Step 8.
STEP 5. Voltage measurement at the electric power steering-ECU connector
(1)The steering is in the neutral position.
(2) Measure the electric power steering-ECU voltage without disconnecting the connector (by backprobing).
(3)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(4)Measure the voltage between the C-141-1 electric power steering-ECU connector terminal No.30 and No.31.
OK: 5± 0.2 V
Q. Is the check result normal?
YES Go to Step 6.
NO Replace the Steering gear and linkage assembly (Refer to Electrical Power Steering System (EPS)). Then go to Step 8.
STEP 6. Using scan tool MB991958, check the data list
(1)The steering is in the neutral position.
(2)Check the following data list Data List Reference Table.
- Item No. 03: Torque sensor(power supply)
Q. Is the check result normal?
YES Go to Step 8.
NO Go to Step 7.
STEP 7. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the DTC is set.
Q. Is the DTC C1514 set?
YES Replace the electric power steering-ECU (Refer to Service and Repair). Then go to Step 8.
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).
STEP 8. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the DTC is set.
Q. Is the DTC C1514 set?
YES Return to Step 1.
NO This diagnosis is complete.