Lexus NX: Vehicle Identification Malfunction (C1789)
DESCRIPTION
- When the absorber control ECU has not acquired the vehicle identification information, DTC C1789 is stored. When the vehicle identification information is correctly acquired, this DTC is cleared. Vehicle identification information is automatically acquired when the system enters test mode.
- If an incorrect hybrid vehicle control ECU is installed, the vehicle specifications and data will not match and DTC C1789 will be stored.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Warning Indicate |
|---|---|---|---|---|
| C1789 | Vehicle Identification Malfunction | Either condition is met:
|
| Does not come on |
CAUTION / NOTICE / HINT
NOTICE:
- Before performing troubleshooting, inspect the connectors of related circuits.
-
If DTC C1781 (Suspension Control ECU Malfunction) is output at the same time, perform troubleshooting for C1781 first.
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-
If DTC C1782 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782 first.
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Before replacing the absorber control ECU, perform all of the following again: 1) symptom simulation ; 2) DTC inspection ; and 3) Techstream inspection (ECU Data List or Active Test ). If no malfunctions are found in other areas, replace the absorber control ECU.
-
When the absorber control ECU is replaced, switch to test mode and check that all test mode DTCs are cleared when their respective deletion conditions are met.
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PROCEDURE
| 1. | CHECK FOR DTC (CAN COMMUNICATION SYSTEM) |
(a) Check for DTCs.
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| Result | Proceed to |
|---|---|
| CAN DTC is not output | A |
| CAN DTC is output | B |
| B | .gif) | GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) |
|
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| 2. | CHECK VEHICLE IDENTIFICATION INFORMATION STATUS |
(a) Check that vehicle identification information has been stored.
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| Result | Proceed to |
|---|---|
| Information stored | A |
| Information not stored | B |
| B | | PERFORM VEHICLE IDENTIFICATION INFORMATION REGISTRATION |
|
| 3. | READ VALUE USING TECHSTREAM (STOP AND START LEARNING STATUS) |
(a) Turn the power switch off.
(b) Connect the Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Turn the Techstream on.
(e) Enter the following menus: Chassis / Air suspension / Data List.
Chassis > Air suspension > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Stop and Start Learning Status | Learning status of stop and start setting availability after vehicle identification information registration is performed | Unset, OFF or ON | OFF | When "Unset", DTC C1789 is output. |
| Tester Display |
|---|
| Stop and Start Learning Status |
(f) Check the value displayed on the Techstream.
OK:
The display is as specified in the normal condition column.
| NG | | REPLACE ABSORBER CONTROL ECU |
|
| 4. | CHECK RELATED PART |
(a) If the DTC was output as a result of the replacement of a related part, replace the part with one that has a correct part number.
| Related Part | Hybrid vehicle control ECU |
NOTICE:
When removing a related part to check it, be sure to follow the appropriate procedures and precautions.
Refer to the following procedures to remove the hybrid vehicle control ECU.
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HINT:
If parts have not been replaced and DTC C1789 is output, there may be an internal malfunction in the absorber control ECU. Therefore, replace the absorber control ECU.
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|
| 5. | CHECK FOR DTC |
(a) Clear the DTCs.
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(b) Turn the power switch off.
(c) Check if DTC C1789 is output.
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OK:
DTC C1789 is not output.
| OK | | END |
| NG | | REPLACE ABSORBER CONTROL ECU |
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