Code No.B16A7 Tail lamp (RH) circuit short <Short circuit in the position lamp (RH) circuit or the tail lamp (RH) 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 or the tail lamp circuit, the ETACS-ECU sets the diagnosis code No. B16A7.

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 the diagnosis code No. B16A7 if no load is detected.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Bulb check


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

Q. Is the check result normal?

Go to Step 2.

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

STEP 2. Resistance measurement at the headlamp assembly (position: RH) connector, rear combination lamp (tail: 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 headlamp assembly (position: RH) connector (earth terminal) and body earth.
  • Measure the resistance between the rear combination lamp (tail: RH) connector (earth terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 4.

Go to Step 3.

STEP 3. Check of open circuit in earth lines between the headlamp assembly (position: RH) connector , rear combination lamp (tail: RH) connector and body earth.


Q. Is the check result normal?

Go to Step 5.

Repair the connector(s) or wiring harness.

STEP 4. Check of short to power supply, short to earth, and open circuit in (TAR1, TAR2) lines between the headlamp assembly (position: RH) connector , rear combination lamp (tail: RH) connector and ETACS-ECU connector.


Q. Is the check result normal?

Go to Step 5.

Repair the connector(s) or wiring harness.

STEP 5. Check whether the diagnosis code is reset.


(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.

The diagnosis is complete.