DESCRIPTION
The headlight leveling ECU receives the vehicle speed signal from the combination meter.
WIRING DIAGRAM
INSPECTION PROCEDURE
Tech Tips
After replacing the headlight leveling ECU, initialization of the ECU is necessary Click here.
PROCEDURE
READ VALUE USING INTELLIGENT TESTER (VEHICLE SPEED)
Using the intelligent tester, read the Data List Click here.
| Tester Display | Measurement Item/Range | Normal Condition | Diagnostic Note |
|---|---|---|---|
| Vehicle Speed | Vehicle speed / 0 to 327.67 km/h | Actual vehicle speed | - |
| OK |
|---|
| The display is as specified in the normal condition column. |
| NG |
|
CHECK COMBINATION METER ASSEMBLY Click here |
| OK |
|
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here
CHECK COMBINATION METER ASSEMBLY
| *a | Component with harness connected (Combination Meter Assembly) |
Remove the combination meter with its connector still connected Click here.
Connect an oscilloscope to the combination meter connector.
Check the waveform.
| Item | Content |
|---|---|
| Terminal No. (Symbol) | C27-6 - Body ground |
| Tool setting | 5 V/DIV., 20 ms./DIV. |
| Condition | Vehicle is driven at approximately 20 km/h (12 mph) |
| OK |
|---|
| Waveform is as shown in the illustration. |
Tech Tips
When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.
| NG |
|
GO TO METER / GAUGE SYSTEM Click here |
| OK |
|
CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - HEADLIGHT LEVELING ECU ASSEMBLY)
Disconnect the C27 combination meter connector.
Disconnect the H17 headlight leveling ECU connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here