54A-CODE NO.B16A8 TAIL LIGHT (LH) CIRCUIT SHORT

DTC B16A8: Taillight (LH) circuit short <Short circuit in the position light (LH) circuit, the taillight (LH) circuit, the rear side marker light (LH) circuit or the license plate light circuit>

caution

Whenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TROUBLE JUDGMENT

When an short circuit is detected in the position light circuit, the taillight circuit, the rear side marker light circuit or the license plate light circuit, the ETACS-ECU sets DTC B16A8.

TECHNICAL DESCRIPTION (COMMENT)

The problem detection of the position light, the taillight, the rear side marker light or license plate light is made based on the digital feed back signal (input signal to ETACS-ECU) which operates the taillight. When the ignition switch is "ON", the ETACS-ECU determines the position light circuit, the taillight circuit, the rear side marker light circuit or the license plate 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 the DTC B16A8 if no load is detected.

TROUBLESHOOTING HINTS

The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
Malfunction of bulbs
Malfunction of the ETACS-ECU

DIAGNOSIS

Required Special Tools:

MB992006: Extra fine probe
MB991223: Harness set

STEP 1. Bulb check.

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

Is the check result normal?

Go to Step 2

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

STEP 2. Check headlight assembly (position light: LH) connector A-43, rear combination light (taillight/side marker light: LH) connector D-19, license plate light (LH) connector G-19 and license plate light (RH) connector G-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Is headlight assembly (position light: LH) connector A-43, rear combination light (taillight/side marker light: LH) connector D-19, license plate light (LH) connector G-19 and license plate light (RH) connector G-05 in good condition?

Go to Step 3

Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection

STEP 3. Resistance measurement at headlight assembly (position light: LH) connector A-43, rear combination light(taillight/side marker light: LH) connector D-19, license plate light (LH) connector G-19 and license plate light (RH) connector G-05.

(1) Disconnect the connector, and measure at the wiring harness side.

(2) Measure the resistance between the connector of light which does not illuminate and the body ground.

Measure the resistance between headlight assembly (position light: LH) connector A-43 (terminal 4) and body ground.
Measure the resistance between the rear combination light (LH) connector D-19 (terminal 4) and the body ground.
Measure the resistance between license plate light (LH) connector G-19 (terminal 1) and body ground.
Measure the resistance between license plate light (RH) connector G-05 (terminal 1) and body ground.

OK: The measured value should be continuity exists (2 ohms or less).

Does the measured resistance value correspond with this range?

Go to Step 5

Go to Step 4

STEP 4. Check the wiring harness between headlight assembly connector, rear combination light connector or license plate light and the body ground.

Check the ground line for short circuit.

Check the wiring harness between headlight assembly (position light: LH) connector A-43 (terminal 4) and the body ground.
Check the wiring harness between rear combination light (taillight/side marker light: LH) connector D-19 (terminal 4) and the body ground.

Check the wiring harness between license plate light (LH) connector G-19 (terminal 1) and the body ground.

note	Also 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 .

Check the wiring harness between license plate light (RH) connector G-05 (terminal 1) and the body ground.

note	Also 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 headlight assembly connector, rear combination light connector or license plate light and ground in good condition?

Go to Step 7

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. Check ETACS-ECU connectors C-403 and C-413 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Is ETACS-ECU connectors C-403 and C-413 in good condition?

Go to Step 6

Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection

STEP 6. Check wiring harness between headlight assembly connector, rear combination light connector or license plate light and ETACS-ECU connector.

Check the power supply line for short circuit.

Check the wiring harness between headlight assembly (position light: LH) connector A-43 (terminal 3) and ETACS-ECU connector C-403 (terminal 3).
Check the wiring harness between rear combination light (taillight/side marker light: LH) connector D-19 (terminal 2) and ETACS-ECU connector C-413 (terminal 10).

Check the wiring harness between license plate light (LH) connector G-19 (terminal 2) and ETACS-ECU connector C-413 (terminal 10).

note	Also check intermediate connectors 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 .

Check the wiring harness between license plate light (RH) connector G-05 (terminal 2) and ETACS-ECU connector C-413 (terminal 10).

note	Also check intermediate connectors 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 headlight assembly connector, rear combination light connector or license plate light and ETACS-ECU connector in good condition?

Go to Step 7

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 7. Using scan tool MB991958, Check whether the diagnostic trouble code is set again.

(1)

caution

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958. Refer to "How to connect scan too (M.U.T.-III)

(2) Turn the ignition switch to the "ON" position.

(3) Erase the DTC.

(4) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.

(5) Check if DTC is set.

Is the DTC set?

Replace the ETACS-ECU.

The procedure is complete.