Code No.21 Malfunction of the Height Sensor (Rear)


caution Whenever the ECU is replaced, ensure that the communication circuit is normal.














TROUBLE JUDGMENT
When the headlamp automatic levelling-ECU receives an abnormal voltage signal from the rear height sensor, diagnosis code No. 21 is set.

COMMENTS ON TROUBLE SYMPTOM
The rear height sensor, the headlamp automatic levelling-ECU, or wiring harness and connectors between the two may be defective.

PROBABLE CAUSES

  • Malfunction of the rear height sensor
  • Malfunction of the headlamp automatic levelling-ECU
  • Damaged wiring harness and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: E-117 Rear height sensor connector

Q. Is the check result normal?
Go to Step 2.
Repair the defective connector.

STEP 2. Check the rear height sensor.
Check that the rear height sensor works normally (Refer to ).

Q. Is the check result normal?
Go to Step 3.
Replace the rear height sensor.

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. Check the wiring harness from E-117 rear height sensor connector (terminal No. 2, 1 and 3) to D-125 headlamp automatic levelling-ECU connector (terminal No. 18, 16 and 20).

  • Check the power supply lines, earth lines and communication lines for open circuit.
note Prior to the wiring harness inspection, check intermediate connectors E-120, D-221 and repair if necessary.

Q. Is the check result normal?
Go to Step 5.
Repair the wiring harness.

STEP 5. Check whether the diagnosis code is reset.

Q. Is diagnosis code No.21 set?
Replace the headlamp automatic levelling-ECU.
A poor connection, open circuit, or other intermittent malfunctions between the rear height sensor and the headlamp automatic levelling ECU. (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .)