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DTC B16A8: Taillight (LH) circuit short <Short circuit in the taillight control circuit>
 
 
cautionWhenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
 
 
TROUBLE JUDGMENT
When the short circuit is detected in the following light circuit, the ETACS-ECU sets DTC No. B16A8.
  • Taillight
  • Parking light
  • License plate light
  • Front side-marker light
  • Rear side-marker light
 
 
TECHNICAL DESCRIPTION (COMMENT)
The problem detection of 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 DTC No. B16A8 if the load is detected on the line.
 
 
TROUBLESHOOTING HINTS
  • The headlight assembly (LH) may be defective. <Parking light/front side-marker light>
  • The rear combination lamp unit (LH) may be defective. <Taillight/rear side-marker light>
  • The liftgate light unit (LH) may be defective. <Taillight>
  • The license plate bulb may be defective.
  • The license plate socket 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. Check ETACS-ECU connector C-413, rear combination light (taillight/rear side-marker light: LH) connector D-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is ETACS-ECU connector C-413, rear combination light (taillight/rear side-marker light: LH) connector D-19 in good condition?
Go to Step 2.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 2. Check the ground circuit to the rear combination light (taillight/rear side-marker light: LH). Measure the resistance at rear combination light (taillight/rear side-marker light: LH) connector D-19.
(1) Disconnect rear combination light (taillight/rear side-marker light: LH) connector D-19 and measure the resistance available at the wiring harness side of the connector.
(2) Measure the resistance value between rear combination light (taillight/rear side-marker light: LH) connector D-19 terminal 3 and ground.
  • The resistance should be 2 ohms or less.
Is the measured resistance 2 ohms or less?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check the wiring harness between rear combination light (taillight/rear side-marker light: LH) connector D-19 (terminal 3) and the ground.
Check the ground wires for open circuit.
Is the wiring harness between rear combination light (taillight/rear side-marker light: LH) connector D-19 (terminal 3) and the ground in good condition?
Go to Step 4.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 4. Check the wiring harness between rear combination light (taillight/rear side-marker light: LH) connector D-19 (terminal 4) and ETACS-ECU connector C-413 (terminal 10).
  • Check the power supply line for open circuit and short circuit.
Is the wiring harness between rear combination light (taillight/rear side-marker light: LH) connector D-19 (terminal 4) and ETACS-ECU connector C-413 (terminal 10) in good condition?
Go to Step 5.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 5. Using scan tool MB991958, check whether the DTC is set again.
Check again if the DTC is set in the ETACS.
(1) Erase the DTC.
(2) Lighting operation of a taillight is performed.
(3) Check if DTC is set.
Is the DTC set?
Go to Step 6.
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 6. Using scan tool MB991958, check whether the DTC is set again.
Check again if the DTC is set in the ETACS.
(1) Erase the DTC.
(2) Disconnect the rear combination light (taillight/rear side-marker light: LH) connector.
(3) Lighting operation of a taillight is performed.
(4) Check if DTC is set.
Is the DTC set?
Go to Step 7.
Replace the rear combination light unit (LH).
 
STEP 7. Check ETACS-ECU connector C-413, liftgate light (taillight: LH) connector G-27 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is connector in good condition?
Go to Step 8.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 8. Check the ground circuit to the liftgate light (taillight: LH). Measure the resistance at liftgate light (taillight: LH) connector G-27.
(1) Disconnect liftgate light (taillight: LH) connector G-27 and measure the resistance available at the wiring harness side of the connector.
(2) Measure the resistance value between liftgate light (taillight: LH) connector G-27 terminal 4 and ground.
  • The resistance should be 2 ohms or less.
Is the measured resistance 2 ohms or less?
Go to Step 10.
Go to Step 9.
 
STEP 9. Check the wiring harness between liftgate light (taillight: LH) connector G-27 (terminal 4) and ground in good condition?
  • Check the ground wires for open circuit.
noteAlso check intermediate connector G-23 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector G-23 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection .
Is the wiring harness between liftgate light (taillight: LH) connector G-27 (terminal 4) and the ground in good condition?
Go to Step 10.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 10. Check the wiring harness between liftgate light (taillight: LH) connector G-27 (terminal 1) and ETACS-ECU connector C-413 (terminal 10).
  • Check the power supply line for open circuit and short circuit.
noteAlso check intermediate connector G-23 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector G-23 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection .
Is the wiring harness between liftgate light (taillight: LH) connector G-27 (terminal 1) and ETACS-ECU connector C-413 (terminal 10) in good condition?
Go to Step 11.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 11. Using scan tool MB991958, check whether the diagnostic trouble code is set again.
Check again if the DTC is set in the ETACS.
(1) Erase the DTC.
(2) Lighting operation of a taillight is performed.
(3) Check if DTC is set.
Is the DTC set?
Go to Step 12.
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 12. Using scan tool MB991958, check whether the diagnostic trouble code is set again.
Check again if the DTC is set in the ETACS.
(1) Erase the DTC.
(2) Disconnect the liftgate light (taillight: LH) connector.
(3) Lighting operation of a taillight is performed.
(4) Check if DTC is set.
Is the DTC set?
Go to Step 13.
Replace the liftgate light unit (LH).
 
STEP 13. Connector check.Check headlight assembly (parking light/front side-marker light: LH) connector A-43, ETACS-ECU connector C-403 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
  • Headlight assembly (parking light/front side-marker light: LH) connector A-43
  • ETACS-ECU connector C-403
Is connector in good condition?
Go to Step 14.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 14. Check the ground circuit to the headlight assembly (parking light/front side-marker light: LH) connector. Measure the resistance at headlight assembly (parking light/front side-marker light: LH) connector A-43.
(1) Disconnect headlight assembly (parking light/front side-marker light: LH) connector A-43 and measure the resistance available at the wiring harness side of the connector.
(2) Measure the resistance value between headlight assembly (parking light/front side-marker light: LH) connector A-43 terminal No. 2 and ground.
  • The resistance should be 2 ohms or less.
Is the measured resistance 2 ohms or less?
Go to Step 16.
Go to Step 15.
 
STEP 15. Check the wiring harness between headlight assembly (parking light/front side-marker light: LH) connector A-43 (terminal No. 2) and the ground.
  • Check the ground wires for open circuit.
Is the wiring harness between headlight assembly (parking light/front side-marker light: LH) connector A-43 (terminal No. 2) and the ground in good condition?
Go to Step 16.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 16. Check the wiring harness between headlight assembly (parking light/front side-marker light: LH) connector A-43 (terminal No. 6) and the ETACS-ECU connector C-403 (terminal No. 3).
  • Check the power supply line for open circuit and short circuit.
Is the wiring harness between headlight assembly (parking light/front side-marker light: LH) connector A-43 (terminal No. 6) and the ETACS-ECU connector C-403 (terminal No. 3) in good condition?
Go to Step 17.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 17. Using scan tool MB991958, check whether the DTC is set again.
(1) Erase the DTC.
(2) Lighting operation of a taillight is performed.
(3) Check if DTC is set.
Is the DTC set?
Go to Step 18.
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 18. Using scan tool MB991958, check whether the DTC is set again.
(1) Erase the DTC.
(2) Disconnect the headlight assembly (parking light/front side-marker light: LH) connector.
(3) Lighting operation of a taillight is performed.
(4) Check if DTC is set.
Is the DTC set?
Go to Step 19.
Replace the headlight body (LH).
 
STEP 19. Check ETACS-ECU connector C-413, license plate light (RH) connector G-05, license plate light (LH) connector G-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is ETACS-ECU connector C-413, license plate light (RH) connector G-05, license plate light (LH) connector G-19 in good condition?
Go to Step 20.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 20. Check the ground circuit to the license plate light (RH) connector, license plate light (LH) connector. Measure the resistance at license plate light (RH) connector G-05, license plate light (LH) connector G-19.
(1) Disconnect license plate light (RH) connector G-05, license plate light (LH) connector G-19 and measure the resistance available at the wiring harness side of the connector.
(2) Measure the resistance value between license plate light (RH) connector G-05 terminal 1, license plate light (LH) connector G-19 terminal 1 and ground.
  • The resistance should be 2 ohms or less.
Is the measured resistance 2 ohms or less?
Go to Step 22.
Go to Step 21.
 
STEP 21. Check the wiring harness between license plate light (RH) connector G-05 (terminal 1), license plate light (LH) connector G-19 (terminal 1) and the ground.
Check the ground wires for open circuit.
noteAlso check intermediate connectors G-23 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors G-23 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection .
Is the wiring harness between license plate light (RH) connector G-05 (terminal 1), license plate light (LH) connector G-19 (terminal 1) and the ground in good condition?
Go to Step 22.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 22. Check the wiring harness between license plate light (RH) connector G-05 (terminal 2), license plate light (LH) connector G-19 (terminal 2) and ETACS-ECU connector C-413 (terminal 10).
  • Check the power supply line for open circuit and short circuit.
noteAlso check intermediate connectors G-23 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors G-23 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection .
Is the wiring harness between license plate light (RH) connector G-05 (terminal 2), license plate light (LH) connector G-19 (terminal 2) and ETACS-ECU connector C-413 (terminal 10) in good condition?
Go to Step 23.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 23. Using scan tool MB991958, check whether the DTC is set again.
(1) Erase the DTC.
(2) Lighting operation of a taillight is performed.
(3) Check if DTC is set.
Is the DTC set?
Go to Step 24.
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 24. Using scan tool MB991958, check whether the DTC is set again.
(1) Erase the DTC.
(2) Disconnect the G-05 license plate light (RH) or G-19 license plate light (LH) connector.
(3) Lighting operation of a taillight is performed.
(4) Check if DTC is set.
Is the DTC set?
Replace the ETACS-ECU.
Replace the license plate light (RH) socket or license plate light (LH) socket.