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DTC B16A4 Turn signal(RH) bulb outage <From 22 Model year>
 
 
caution
  • Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
 
 
DIAGNOSTIC FUNCTION
When the right bulb of turn-signal light is blown, the ETACS-ECU sets DTC B16A4.
 
 
TROUBLE JUDGMENT
The ETACS-ECU sets DTC B16A4 under the following conditions.
  1. DTC B16A4 is set if the front LED turn-signal light fail signal is ON when the turn-signal light (right side) is turned on with no DTC set. <Front side>
  2. With the DTC not set, if there is a malfunction to the right turn-signal light bulb, the blown right bulb counter counts once when the illumination of hazard or turn-signal light (right side) is attempted. <Rear side>
  3. If the blown right bulb counter reaches "3," DTC B16A4 is set. <Rear side>
 
 
TROUBLESHOOTING HINTS
  • The turn-signal light bulb (right side)
  • The ETACS-ECU may be defective
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
DIAGNOSIS
Required Special Tools:
  • MB992006: Extra fine probe
  • MB991223: Harness set
STEP 1. Using scan tool (M.U.T.-IIISE), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect Scan tool (M.U.T.-IIISE) ."
(2) Using the ETACS-ECU data list, check the signal related of turn-signal light.
 
Item No.Item nameCondition
119LED headlight fail/LED turn failON or OFF
Is the "ON" displayed?
Go to Step 2.
Go to Step 9.
 
STEP 2. Resistance measurement at the front combination light (TURN: RH) connector [E terminal].
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the front combination light (TURN: RH) connector [E terminal] and body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in E line between front combination light (TURN: RH) connector and the body ground.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Voltage measurement at the front combination light (TURN: RH) connector [(+B) terminal].
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between the front combination light (TURN: RH) connector [(+B) terminal] and body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check of open circuit in +B line between front combination light (TURN: RH) connector and fusible link.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
 
STEP 6. Check of open circuit in TR1 line between ETACS-ECU connector and front combination light (TURN: RH) connector.
Is the check result normal?
Go to Step 7.
Repair the connector(s) or wiring harness.
 
STEP 7. Check of open circuit in DLHL line between ETACS-ECU connector and front combination light (TURN: RH) connector.
Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.
 
STEP 8. Check that the turn-signal lights operate.
Is the check result normal?
Go to Step 14.
Replace the front combination light assembly (RH).
 
STEP 9. Bulb check
Check whether the bulb of turn-signal light which does not illuminate is normal.
Is the check result normal?
Go to Step 10.
Replace the bulb of turn-signal light which does not illuminate.
 
STEP 10. Resistance measurement at the door mirror assembly (RH) connector and rear combination light (TURN: RH) connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the connector terminal of light which does not illuminate and the body ground.
  • Measure the resistance between the door mirror assembly (RH) connector (ground terminal) and the body ground.
  • Measure the resistance between the rear combination light (TURN: RH) connector (ground terminal) and the body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 12.
Go to Step 11.
 
STEP 11. Check of open circuit in ground line between door mirror assembly (RH) connector or rear combination light (TURN: RH) connector and the body ground.
Is the check result normal?
Go to Step 12.
Repair the connector(s) or wiring harness.
 
STEP 12. Check of open circuit in TR2&TR3 line between ETACS-ECU connector and rear combination light (TURN: RH) connector.
Is the check result normal?
Go to Step 13.
Repair the connector(s) or wiring harness.
 
STEP 13. Check of open circuit in TR2&TR3 line between ETACS-ECU connector and door mirror assembly (RH) connector.
Is the check result normal?
Go to Step 14.
Repair the connector(s) or wiring harness.
 
STEP 14. Using scan tool (M.U.T.-IIISE), read the DTC again.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
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 ).