Code No.B16A8 Tail lamp (LH) circuit short <Short circuit in the position lamp (LH) circuit, tail lamp (LH) circuit or the licence plate lamp circuit>


caution
  • Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
  • When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine cannot be started. Register the encrypted code as described in Immobilizer System - How to Register Key ID .)

DIAGNOSTIC FUNCTION


When a short circuit is detected in the position lamp circuit, the tail lamp circuit or the licence plate lamp circuit, the ETACS-ECU sets diagnosis code No. B16A8.

JUDGEMENT CRITERIA


The problem detection of tail lamp is made based on the digital feed back signal (input signal to ETACS-ECU) which operates the tail lamp. When the ignition switch is ON, the ETACS-ECU determines the tail lamp 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 diagnosis code No. B16A8 if no load is detected.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. Determine a trouble spot.


Q. Which of lamp does not work?

Position lamp : Go to Step 2.

Tail lamp : Go to Step 11.

STEP 2. Check the rear combination lamp socket.


Check the continuity at the rear combination lamp socket to confirm whether it is normal.

Q. Is the check result normal?

Go to Step 3.

Replace the rear combination lamp socket (LH).

STEP 3. Resistance measurement at the headlamp assembly (position: LH) connector (earth terminals).


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the headlamp assembly (position: LH) connector (earth terminal) and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

STEP 4. Check of open circuit in earth lines between the headlamp assembly (position: LH) connector and body earth.


Q. Is the check result normal?

Go to Step 9.

Repair the connector(s) or wiring harness.

STEP 5.Check of short to power supply, short to earth, and open circuit in (TAL1) lines between the headlamp assembly (position: LH) connector and ETACS-ECU connector.


Q. Is the check result normal?

Go to Step 6.

Repair the connector(s) or wiring harness.

STEP 6. Resistance measurement at the rear combination lamp (tail: LH) connector (earth terminals).


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the rear combination lamp (tail: LH) connector (earth terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 8.

Go to Step 7.

STEP 7. Check of open circuit in earth lines between the rear combination lamp (tail: LH) connector and body earth



Q. Is the check result normal?

Go to Step 9.

Repair the connector(s) or wiring harness.

STEP 8. Check of short to power supply, short to earth, and open circuit in (TAL2) lines between the rear combination lamp (tail: LH) connector and ETACS-ECU connector.


Q. Is the check result normal?

Go to Step 9.

Repair the connector(s) or wiring harness.

STEP 9. Check whether the diagnosis code is set again.


(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Check if diagnosis code is set.

Q. Is the diagnosis code set?

Go to Step 10.

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 10. Substitute a known good rear combination lamp unit (LH), and check the diagnosis code.


(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Check if diagnosis code is set.

Q. Is the diagnosis code set?

Replace the ETACS-ECU.

Replace the rear combination lamp unit (LH).

STEP 11. Bulb check


Check the bulb(s) of the licence plate lamp that does not illuminate.

Q. Is the check result normal?

Go to Step 12.

Replace the bulb(s) of the lamp that does not illuminate.

STEP 12. Resistance measurement at the tail lamp (LH) connector, licence plate lamp (LH) connector and licence plate lamp (RH) connector (earth terminals).


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the connector terminal of lamp which does not illuminate and the body earth.

  • Measure the resistance between the tail lamp (LH) connector (earth terminal) and body earth.
  • Measure the resistance between the licence plate lamp (LH) connector (earth terminal) and body earth.
  • Measure the resistance between the licence plate lamp (RH) connector (earth terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 14.

Go to Step 13.

STEP 13. Check of open circuit in earth lines between the tail lamp (LH) connector, licence plate lamp (LH) connector or licence plate lamp (RH) connector and body earth.


Q. Is the check result normal?

Go to Step 15.

Repair the connector(s) or wiring harness.

STEP 14.Check of short to power supply, short to earth, and open circuit in (TAL2) lines between the tail lamp (LH) connector, licence plate lamp (LH) connector or licence plate lamp (RH) connector and ETACS-ECU connector


Q. Is the check result normal?

Go to Step 15.

Repair the connector(s) or wiring harness.

STEP 15. Check whether the diagnosis code is set again.


(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Check if diagnosis code is set.

Q. Is the diagnosis code set?

Go to Step 16.

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 16. Substitute a known good tail lamp assembly (LH), and check the diagnosis code.


(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Check if diagnosis code is set.

Q. Is the diagnosis code set?

Replace the ETACS-ECU.

Replace the tail lamp assembly (LH).