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DTC B16A4 Turn signal(RH) bulb outage
 
 
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. 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.
  2. If the blown right bulb counter reaches "3," DTC B16A4 is set.
 
 
TROUBLESHOOTING HINTS
  • The front or rear turn-signal light bulb (right side) may be defective
  • The side turn-signal light assembly (right side) may be defective <Integrated in door mirror type>
  • 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. Bulb check.
Check whether the bulb of turn-signal light which does not illuminate is normal.
Is the check result normal?
Go to Step 2.
Replace the bulb of turn-signal light which does not illuminate.
 
STEP 2. Resistance measurement at the front turn-signal light (RH) connector, 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 front turn-signal light (RH) connector (ground terminal) 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 4.
Go to Step 3.
 
STEP 3. Check of open circuit in ground line between front turn-signal light (RH) connector, door mirror assembly (RH) connector or rear 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. Check of open circuit in TR1 line between ETACS-ECU connector and front turn-signal light (RH) connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. 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 6.
Repair the connector(s) or wiring harness.
 
STEP 6. 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 7.
Repair the connector(s) or wiring harness.
 
STEP 7. Using scan tool (M.U.T.-IIISE), read the DTC again.
(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) Erase the DTC.
(3) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(4) 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 ).