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DTC P0703: Malfunction of Stoplight Switch
 
 

 
 
 
 
DIAGNOSTIC FUNCTION
TCM detects malfunction using the stoplight switch signal sent from the ETACS-ECU.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Drive the vehicle at 30 km/h (19 mph) or more for 10 seconds, and then turn the ignition switch to the "LOCK" (OFF) position. In this sequential operation, no variation has been found in the stoplight switch input signal in two consecutive times.
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
LOGIC FLOW CHARTS (Monitor Sequence)
 
 
DTC SET CONDITIONS
Check Conditions
  • Vehicle speed: 30 km/h (19 mph) or more.
  • Voltage of battery: 9 volts or more.
  • Voltage of battery: 16 volts or less.
Judgment Criteria
  • The change of stoplight switch signal during driving cycle: no occurrence (10 seconds × 2 times).
 
 
OBD-II DRIVE CYCLE PATTERN
Drive the vehicle for 10 seconds or more at 30 km/h (19 mph) or higher (2 drive cycle)
 
 
PROBABLE CAUSES
  • Malfunction of the CAN bus
  • Malfunction of the stoplight switch
  • Damaged wiring harness and connectors
  • Malfunction of TCM
  • Malfunction of ETACS-ECU
 
 
DIAGNOSIS
STEP 1. M.U.T.-III CAN bus diagnostics
Use scan tool to perform the CAN bus diagnosis.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C, Troubleshooting - Diagnosis Code Chart ).
 
STEP 2. M.U.T.-III data list
Item 50: Brake switch
OK: The service data changes in response to the brake operation.
Is the check result normal?
Intermittent malfunction
Go to Step 3.
 
STEP 3. Check the following connector:
  • C-403 ETACS-ECU connector
  • C-410 ETACS-ECU connector
  • C-25 Stoplight switch connector
  • C-28 Intermediate connector
Check the contact status of the terminals.
Is the check result normal?
Go to Step 4.
Repair the defective connector.
 
STEP 4. Stoplight Switch Check
Refer to GROUP 35A, Brake Pedal .
Is the check result normal?
Go to Step 5.
Replace the stoplight switch.
 
STEP 5. Check for open circuit in the wiring harness between the stoplight switch connector and the ETACS-ECU connector.
Between C-25 stoplight switch connector (terminal No.1) and C-403 ETACS-ECU harness-side connector (terminal No.1)
Is the check result normal?
Go to Step 6.
Repair the wiring harness.
 
STEP 6. Check for open circuit or short to ground in wiring harness between the ETACS-ECU connector and the stoplight relay connector.
Between C-410 ETACS-ECU harness-side connector (terminal No.16) and C-28 intermediate connector (terminal No.24)
Is the check result normal?
Go to Step 7.
Repair the wiring harness.
 
STEP 7. Check for open circuit or short to ground in wiring harness between the stoplight switch connector and the stoplight relay connector.
Between C-25 stoplight switch connector (terminal No.2) and C-28 intermediate connector (terminal No.24)
Is the check result normal?
Go to Step 8.
Repair the wiring harness.
 
STEP 8. Symptom recheck after erasing diagnostic trouble code
Is the check result normal?
Intermittent malfunction
Replace the ETACS-ECU, and then go to Step 9.
 
STEP 9. Symptom recheck after erasing diagnostic trouble code
Is the check result normal?
Intermittent malfunction
Replace TCM.