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DTC B16A0: Taillight (RH) circuit open<Open circuit in the taillight control circuit>
DTC B16A7: Taillight (RH) circuit short<Short circuit in the taillight control circuit>
 
 
cautionBefore replacing the ECU, ensure that the powersupply circuit, the ground circuit and the communicationcircuit are normal.
 
 
 
 
TROUBLE JUDGMENT
When an open circuit is detected in the following circuit,the ETACS-ECU sets DTC B16A0. If a short circuit is detected, DTC B16A7 is set.
  • Taillight
  • Side marker light
  • Position light
  • Glove box light
 
 
TECHNICAL DESCRIPTION (COMMENT)
The problem detection of the each light is made based on the digital feed back signal (input signal to ETACS-ECU) which operates the each light. When the ignition switch is "ON", the ETACS-ECU determines the each light circuit state from the load placed on the line. After 100 ms has elapsed since the start of the check, the ETACS-ECU performs a sampling with each 10 ms. If an abnormality is detected, it increases the counter by 2, and when no abnormality is detected, it decreases the counter by 1. Once the counter reaches "10", the ETACS-ECU sets the DTC B16A0 if the load is detected on the line, and sets the DTC B16A7 if no load is detected.
 
 
TROUBLESHOOTING HINTS
  • The rear combination light unit (RH) may be defective
  • The position light bulb (RH) may be defective
  • The headlight body may be defective
  • The glove box light bulb may be defective
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • The ETACS-ECU may be defective
 
 
DIAGNOSIS
Required Special Tools:
  • MB992006: Extra fine probe
  • MB991223: Harness set
STEP 1. Resistance measurement at the rear combination light (RH) connector (ground terminals).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the rear combination light (RH) connector (ground terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 3.
Go to Step 2.
 
STEP 2. Check of open circuit in ground lines between the rear combination light (RH) connector and ground.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness. Then go to Step 3.
 
STEP 3. Check of short to power supply and open circuit in power supply lines between the rear combination light (RH) connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness. Then go to Step 4.
 
STEP 4. Using scan tool (M.U.T.-III), Check whether the diagnostic trouble code is stored again.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect Scan Tool (M.U.T.-III)."
(2) Erase the DTC.
(3) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(4) Check if DTC is stored.
Is the DTC stored?
Go to Step 5.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).
 
STEP 5. Substitute a known good rear combination light unit (RH), and check whether the DTC is stored again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
Is the DTC stored?
Go to Step 12.
Replace the rear combination light unit (RH).
 
STEP 6. Check the rear side marker light bulb (RH).
Check the continuity at the rear side marker light bulb (RH) to confirm whether it is normal.
Is the check result normal?
Go to Step 7.
Replace the rear side marker light bulb (RH). Then go to Step 7.
 
STEP 7. Resistance measurement at the rear side marker light (RH) connector (ground terminals).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the rear side marker light (RH) connector (ground terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 9.
Go to Step 8.
 
STEP 8. Check of open circuit in ground lines between the rear side marker light (RH) connector and ground.
Is the check result normal?
Go to Step 9.
Repair the connector(s) or wiring harness. Then go to Step 9.
 
STEP 9. Check of short to power supply and open circuit in power supply lines between the rear side marker light (RH) connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 10.
Repair the connector(s) or wiring harness. Then go to Step 10.
 
STEP 10. Using scan tool (M.U.T.-III), Check whether the diagnostic trouble code is stored again.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect Scan Tool (M.U.T.-III)."
(2) Erase the DTC.
(3) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(4) Check if DTC is stored.
Is the DTC stored?
Go to Step 11.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).
 
STEP 11. Substitute a known good rear side marker light unit (RH), and check whether the DTC is stored again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
Is the DTC stored?
Go to Step 12.
Replace the rear side marker light unit (RH).
 
STEP 12. Check the position light bulb (RH).
Check the continuity at the position light bulb (RH) to confirm whether it is normal.
Is the check result normal?
Go to Step 13.
Replace the position light bulb (RH). Then go to Step13.
 
STEP 13. Resistance measurement at the headlight assembly (position: RH) connector (ground terminals).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the headlight assembly (position: RH) connector (ground terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 15.
Go to Step 14.
 
STEP 14. Check of open circuit in ground lines between the headlight assembly (position: RH) connector and ground.
Is the check result normal?
Go to Step 15.
Repair the connector(s) or wiring harness. Then go to Step 15.
 
STEP 15. Check of short to power supply and open circuit in power supply lines between the headlight assembly (position: RH) connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 16.
Repair the connector(s) or wiring harness. Then go to Step 16.
 
STEP 16. Using scan tool (M.U.T.-III), Check whether the DTC is stored again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
Is the DTC stored?
Go to Step 29.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).
 
STEP 17. Check the continuity of the heated seat (RH) connector.
Check the continuity at the heated seat (RH).
Terminal numberStandard value
1 - 2Continuity exists (2 ohms or less)
Is the check result normal?
Go to Step 19.
Go to Step 18.
 
STEP 18. Check the continuity of the heated seat switch (RH) connector.
Refer to GROUP 52A - Front seat assembly - Inspection, continuity test of heated seat switch.
Is the check result normal?
Replace the heated seat (RH). Then go to Step 19.
Replace the heated seat switch (RH). Then go to Step19.
 
STEP 19. Resistance measurement at the heated seat (RH) connector (ground terminals).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the heated seat (RH) connector (ground terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 21.
Go to Step 20.
 
STEP 20. Check of open circuit in ground lines between the heated seat (RH) connector and ground.
Is the check result normal?
Go to Step 21.
Repair the connector(s) or wiring harness. Then go to Step 21.
 
STEP 21. Check of short to power supply and open circuit in power supply lines between the heated seat (RH) connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 22.
Repair the connector(s) or wiring harness. Then go to Step 22.
 
STEP 22. Using scan tool (M.U.T.-III), Check whether the DTC is stored again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
Is the DTC stored?
Go to Step 23.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).
 
STEP 23. Check the continuity of the heated seat (LH) connector.
Check the continuity at the heated seat (LH).
Terminal numberStandard value
1 - 2Continuity exists (2 ohms or less)
Is the check result normal?
Go to Step 25.
Go to Step 24.
 
STEP 24. Check the continuity of the heated seat switch (LH) connector.
Refer to GROUP 52A - Front seat assembly - Inspection, continuity test of heated seat switch.
Is the check result normal?
Replace the heated seat (LH). Then go to Step 25.
Replace the heated seat switch (LH). Then go to Step25.
 
STEP 25. Resistance measurement at the heated seat (LH) connector (ground terminals).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the heated seat (LH) connector (ground terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 27.
Go to Step 26.
 
STEP 26. Check of open circuit in ground lines between the heated seat (LH) connector and ground.
Is the check result normal?
Go to Step 27.
Repair the connector(s) or wiring harness. Then go toStep 27.
 
STEP 27. Check of short to power supply and open circuit in power supply lines between the heated seat (LH) connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 28.
Repair the connector(s) or wiring harness. Then go toStep 28.
 
STEP 28. Using scan tool (M.U.T.-III), Check whether the DTC is stored again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
Is the DTC stored?
Go to Step 29.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).
 
STEP 29. Check the glove box light bulb.
Check the continuity at the glove box light bulb to confirm whether it is normal.
Is the check result normal?
Go to Step 30.
Replace the glove box light bulb. Then go to Step 30.
 
STEP 30. Check of short to power supply and open circuit in power supply lines between the glove box light connector and ETACS-ECU connector.
Is the check result normal?
Go to Step 31.
Repair the connector(s) or wiring harness. Then go to Step 31.
 
STEP 31. Check of open circuit in ground lines between the glove box light connector and ground.
Is the check result normal?
Go to Step 32.
Repair the connector(s) or wiring harness. Then go to Step 32.
 
STEP 32. Using scan tool (M.U.T.-III), Check whether the DTC is stored again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
Is the DTC stored?
Replace the ETACS-ECU.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).