Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
DIAGNOSTIC FUNCTION
If a trouble occurs in height sensor, headlamp automatic levelling system warnings are displayed on the multi information display and code No. B2514 is stored.
JUDGEMENT CRITERIA
The headlamp automatic levelling-ECU detects the power supply error of the height sensor (less than 4.2 V, or 5.8 V or more) for 1 second or longer continuously.
PROBABLE CAUSES
Malfunction of the front height sensor
Malfunction of the rear height sensor
Malfunction of the headlamp automatic levelling-ECU
STEP 2. Voltage measurement at the A-05 front height sensor connector.
(1)Disconnect the connector, and measure at the wiring harness-side connector.
(2)Turn the ignition switch to the ON position.
(3)Voltage between the A-05 front height sensor connector terminal No. 1 and the body earth OK: 5 V
Q.
Is the check result normal?
Go to Step 4.
Go to Step 3.
STEP 3. Wiring harness check between the A-05 front height sensor connector terminal No. 1 and the C-112 headlamp automatic levelling-ECU connector terminal No. 21.
note
Before the wiring harness check, check the intermediate connector A-57, and repair that if necessary.
Check the power supply lines for short circuit.
Q.
Is the check result normal?
Go to Step 4.
Repair the wiring harness.
STEP 4. Check whether the diagnosis code is reset.
Q.
Is diagnosis code No. B2514 set?
Go to Step 5.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to cope with Intermittent Malfunctions ).
STEP 6. Voltage measurement at the D-117 rear height sensor connector.
(1)Disconnect the connector, and measure at the wiring harness-side connector.
(2)Turn the ignition switch to the ON position.
(3)Voltage between the D-117 rear height sensor connector terminal No. 1 and the body earth OK: 5 V
Q.
Is the check result normal?
Go to Step 8.
Go to Step 7.
STEP 7. Wiring harness check between the D-117 rear height sensor connector terminal No. 1 and the C-112 headlamp automatic levelling-ECU connector terminal No. 20.
note
Before the wiring harness check, check the intermediate connectors C-131 and D-116, and then repair that if necessary.
Check the power supply lines for short circuit.
Q.
Is the check result normal?
Go to Step 8.
Repair the wiring harness.
STEP 8. Check whether the diagnosis code is reset.
Q.
Is diagnosis code No. B2514 set?
Go to Step 9.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to cope with Intermittent Malfunctions ).
STEP 9. M.U.T.-III data list
Disconnect the front and rear height sensor connector, and check the power supply voltage to the height sensor.
Item No.
Item name
Normal condition
Item 3
HS power supply voltage
5 V
OK: Normal condition is displayed.
Q.
Is the check result normal?
Go to Step 10.
Replace the headlamp automatic levelling-ECU.
STEP 10. Front height sensor check
Check the front height sensor for the internal failure.
(1)Disconnect the rear height sensor connector.
(2)Disconnect the front height sensor connector and connect the special tool test harness (MB991658) as shown. (3)Turn the ignition switch to the ON position. (4)Measure the voltage of sensor connector terminal No. 1. OK: 5 V
Q.
Is the check result normal?
Go to Step 11.
Replace the front height sensor.
STEP 11. Check whether the diagnosis code is reset.
Q.
Is diagnosis code No. B2514 set?
Go to Step 12.
The diagnosis is complete.
STEP 12. Rear height sensor check
Check the rear height sensor for the internal failure.
(1)Disconnect the rear height sensor connector and connect the special tool test harness (MB991658) as shown. (2)Turn the ignition switch to the ON position. (3)Measure the voltage of sensor connector terminal No. 1. OK: 5 V
Q.
Is the check result normal?
Go to Step 13.
Replace the rear height sensor.
STEP 13. Check whether the diagnosis code is reset.
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Go to Step 2.
Repair the defective connector.
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