[ Model - ECLIPSE CROSS / Year - 2018 ]
2018 / ECLIPSE CROSS / EC - Workshop Manual
37 -ELECTRIC POWER STEERING (EPS) > TROUBLESHOOTING > DIAGNOSIS CODE PROCEDURES > C1541 POWER SUPPLY VOLTAGE ABNORMALITY (LOW VOLTAGE)
Code No.C1541 Power supply voltage too low
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code 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
  • Power is supplied to the EPS-ECU from the ignition switch (IG1).
  • Power is supplied to the motor from the EPS-ECU.
 
 
 
FUNCTION
The EPS-ECU monitors the voltage supplied from the ignition switch (IG1) and the voltage of the motor.
 
 
 
TROUBLE JUDGEMENT
Check Conditions
  • Engine start
Judgement Criterion
  • EPS-ECU power supply voltage is less than threshold.
  • The power supply voltage is more than a predetermined voltage stored in the microcomputer, and the microcomputer determines that there is a problem in the power supply system.
Fail Safe, Back Up Function
  • The EPS-ECU is in motor control output limit state, turns on the electric steering warning display, and sets diagnosis code No.C1541.
 
 
 
PROBABLE CAUSES
  • Defective harness wire(s) or connector(s)
  • Short or open circuit between the EPS-ECU and the EPS-ECU or loose connector contact
  • Open circuit between the body earth and the EPS-ECU or loose connector contact
  • Defective battery
  • Charging system failed
  • Malfunction of the EPS-ECU
 
 
 
 
DIAGNOSIS PROCEDURE
STEP 1. Battery check
Refer to GROUP 54A - Battery Test .
Is the battery in good condition?
Go to Step 2.
Replace the battery (Refer to GROUP 54A - Battery ).
 
STEP 2. Charging system check
Refer to GROUP 16 - On-vehicle Service/Alternator Output Line Voltage Drop Test .
Is the charging system in good condition?
Go to Step 3.
Repair or replace the charging system component(s) (Refer to GROUP 16 - Alternator ).
 
STEP 3. M.U.T.-IIISE data list
Check the following data list (Refer to ).
  • Item No. 33: System1 PIG voltage
  • Item No. 34: System2 PIG voltage
  • Item No. 35: IG voltage
Is the check result normal?
Go to Step 10.
Go to Step 4.
 
STEP 4. Voltage measurement at the EPS-ECU connector (+B, GND terminal)
(1) Disconnect the EPS-ECU connector.
(2) Measure the EPS-ECU voltage at the connector side.
(3) Engine start
(4) Measure the voltage between the EPS-ECU connector (+B terminal) and the EPS-ECU connector (GND terminal) or body earth.
OK: Approximately battery positive voltage
Is the check result normal?
Go to Step 8.
Go to Step 5.
 
STEP 5. Check of open circuit in GND line between EPS-ECU connector and body earth.
notePrior to the wiring harness inspection, check intermediate connector and repair if necessary.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
 
STEP 6. Check the fusible link.
Is the check result normal?
Go to Step 7.
Repair the fusible link.
 
STEP 7. Check of short to power supply, short to earth, and open circuit in +B line between fusible link and EPS-ECU connector
notePrior to the wiring harness inspection, check intermediate connector and repair if necessary.
Is the check result normal?
Go to Step 8.
Repair the fusible link, connector(s) or wiring harness.
 
STEP 8. Voltage measurement at the EPS-ECU connector (IG1, GND terminal)
(1) Disconnect the EPS-ECU connector.
(2) Measure the EPS-ECU voltage at the connector side.
(3) Engine start
(4) Measure the voltage between the EPS-ECU connector (IG1 terminal) and the EPS-ECU connector (GND terminal) or body earth.
OK: Approximately battery positive voltage
Is the check result normal?
Go to Step 10.
Go to Step 9.
 
STEP 9. Check of short to power supply, short to earth, and open circuit in IG1 line between EPS-ECU connector and ETACS-ECU connector
notePrior to the wiring harness inspection, check joint connector and repair if necessary.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).
Repair the connector(s) or wiring harness.
 
STEP 10. Check whether the diagnosis code is set again.
(1) Engine start
(2) Check if the diagnosis code is set.
Is the diagnosis code set?
Replace the EPS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).