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DTC C1537 IG signal failure
 
 
cautionWhenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
The EPS-ECU receives IG1 signal and it is used as a switch that activates/deactivate the EPS-ECU.
 
 
 
FUNCTION
The EPS-ECU monitors the IG voltage.
 
 
 
TROUBLE JUDGMENT
Check Conditions
  • Vehicle is running.
Judgment Criterion
  • When judging that the ignition switch has been turned to the "LOCK" (OFF) position during traveling
Fail Safe, Back Up Function
  • When the failure is confirmed, sets the diagnostic trouble code and continues the assist control for a certain period of time.
 
 
 
TROUBLESHOOTING HINTS
cautionThis DTC is also set even when the driver intentionally turns off the ignition switch while driving. In this case, it is not an abnormality of parts and there is no need to replace parts.
  • Defective battery
  • Charging system failed
  • When the driver intentionally turn the ignition switch to the "LOCK" (OFF) position while driving.
  • Defective harness wire(s) or connector(s)
  • Malfunction of the EPS-ECU
 
 
 
 
DIAGNOSIS
STEP 1. Battery check
Also check that the terminals are not loose or dirty. (Refer to GROUP 54A - Battery, On-vehicle Service/ 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/Generator 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 - Generator Assembly Removal and Installation ).
 
STEP 3. Check of open circuit in GND line between EPS-ECU connector and body ground.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Voltage measurement at the EPS-ECU connector (IG terminal)
(1) Disconnect the EPS-ECU connector.
(2) Measure the EPS-ECU voltage at the wiring harness side.
(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between the EPS-ECU connector (IG terminal) and body ground.
OK: System voltage
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position (Engine running).
(4) Drive the vehicle.
(5) Check if the DTC is set.
Is the DTC set?
Replace the EPS motor (EPS-ECU). (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).