Inspection Procedure 2: Neither Right nor Left Automatic Levelling
Operates.
caution |
Whenever the ECU is replaced, ensure that
the power supply circuit, the earth circuit and the
communication circuit are normal.
|
![](../../../img/54/W7B54L058A00ENG.png)
![](../../../img/54/AC608332AB00ENG.png)
![](../../../img/54/AC607450AH00ENG.png)
![](../../../img/54/AC607559AC00ENG.png)
![](../../../img/54/AC607564AQ00ENG.png)
![](../../../img/54/AC607571AQ00ENG.png)
![](../../../img/54/AC607562BD00ENG.png)
![](../../../img/54/AC607569AQ00ENG.png)
OPERATION
When a vehicle is at a standstill or being driven
at a constant speed for 12 seconds or more (except on rough road), the
headlamp automatic levelling-ECU inputs a headlamp LO relay signal,
vehicle speed signal, and height signal for judgement and operates the
levelling.
note |
The automatic levelling during driving at
a constant speed operates only once after starting driving.
The automatic levelling does not work if the vehicle pitch
angle during driving at a constant speed and the vehicle
pitch angle when the vehicle is stopped are the
same.
|
COMMENTS ON TROUBLE SYMPTOM
Assuming that the automatic
levelling diagnosis code is not set, if neither right nor left automatic
levelling operates, the headlamp automatic levelling-ECU, wiring harness
and connectors between the headlamp automatic levelling-ECU and the
front-ECU (headlamp relay: LO), the vehicle speed sensor (vehicle signal
abnormality), or wiring harness and connectors between the headlamp
automatic levelling-ECU and the vehicle speed sensor may be
defective.
PROBABLE CAUSES
- Malfunction of the headlamp automatic levelling-ECU
- Malfunction of the vehicle speed sensor
- Damaged wiring harness and connectors
DIAGNOSIS PROCEDURE
STEP 1. Check the diagnosis code.
Q.
Does the warning lamp blink normally?
Go to Step
2.
Inspection Procedure
1 "Diagnosis code is not set." Refer to ![](../../../buttons/03btn007.png)
STEP 2. Check the speed meter.
Q.
Does the speed meter operate normally?
Go to Step 3.
Carry out
troubleshooting for the speed meter (Refer to Combination Meter -
Troubleshooting
). After the
troubleshooting for the speed meter, go to Step 3.
STEP 3. Connector check: D-125 Headlamp automatic
levelling-ECU connector
Q.
Is the check result normal?
Go to Step
4.
Repair the defective
connector.
STEP 4. Voltage measurement at
D-125 headlamp automatic levelling-ECU connector.
|
(1)Disconnect the connector, and measure at the
wiring harness-side connector.
|
|
(2)Turn "ON" the headlamp switch.
|
|
(3)Voltage between D-125 headlamp automatic
levelling-ECU connector (terminal No. 6) and body
earth. OK: System voltage
|
Q.
Is the check result normal?
Go to Step 6.
Go to Step
5.
STEP 5. Check the wiring harness between
D-125 headlamp automatic levelling-ECU connector (terminal No. 6)
and A-08X front-ECU connector (terminal No. 6).
note |
Prior to the wiring harness inspection,
check intermediate connector D-239, joint connector A-16,
and repair if necessary.
|
- Check the communication lines for open circuit and short
circuit.
Q.
Is the check result normal?
Go to Step
6.
Repair the wiring
harness.
STEP 6. Connector check: C-16
vehicle speed sensor connector and D-125 headlamp automatic
levelling-ECU connector
Q.
Is the check result normal?
Go to Step
7.
Repair the defective
connector.
STEP 7. Check the wiring harness
between D-125 headlamp automatic levelling-ECU connector (terminal
No. 9) and C-16 vehicle speed sensor connector (terminal No.
3).
- Check the communication lines for open circuit.
note |
Prior to the wiring harness inspection,
check intermediate connector D-228, and repair if
necessary.
|
Q.
Is the check result normal?
Go to Step
8.
Repair the wiring
harness.
STEP 8. Retest the
system.
Check that the automatic levelling operates
normally.
Q.
Is the check result normal?
Intermittent malfunction (Refer
to GROUP 00 - How to Use Troubleshooting/Inspection Service
Points - How to Cope with Intermittent Malfunctions
).
Replace the headlamp automatic
levelling-ECU.