Lexus ES: 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 ECM is installed, the vehicle information will not match and DTC C1789 will be stored.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Warning Indicate | Memory |
|---|---|---|---|---|---|
| C1789 | Vehicle Identification Malfunction | One of the following conditions is met:
|
| Does not come on | Yes (Under some of the detection conditions (control map non-retrieval is not stored), DTC is not stored.) |
CAUTION / NOTICE / HINT
NOTICE:
- Before performing troubleshooting, inspect the connectors of related circuits.
-
Before replacing the absorber control ECU, perform all of the following:
-
Symptom simulation.
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-
DTC inspection.
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-
Techstream inspection.
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- If no malfunctions are found in other areas, replace the absorber control ECU.
-
Symptom simulation.
-
After replacing the absorber control ECU with a new one, perform registration of vehicle identification information.
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PROCEDURE
| 1. | CHECK FOR DTCS |
(a) Check for DTCs.
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HINT:
If DTC C1781 is output at the same time, perform troubleshooting for C1781 first.
| Result | Proceed to |
|---|---|
| C1781 and CAN communication malfunction DTC are not output | A |
| C1781 is output | B |
| CAN communication DTC is output | C |
| B | .gif) | GO TO C1781 |
| C | | 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 engine switch off.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine 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 |
|---|---|---|---|---|
| Vehicle Information (Conv/HV) | Vehicle identification information (hybrid vehicle or except hybrid vehicle) | Unknown, Conv or HV | Conv: When vehicle identification normal | When "Unset", DTC C1789 is output. |
| 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: w/o Stop and Start System ON: w/ Stop and Start System | When "Unset", DTC C1789 is output. |
| Air suspension Learning Status | Learning status of air suspension system setting availability after vehicle identification information registration is performed | Unset, OFF or ON | OFF | When "Unset", DTC C1789 is output. |
| Tester Display |
|---|
| Vehicle Information (Conv/HV) |
| Stop and Start Learning Status |
| Air suspension 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 | ECM |
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 ECM.
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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.
| Result | Proceed to |
|---|---|
| The related part has an incorrect part number | A |
| The related part has the correct part number, or a related part and absorber control ECU have not been replaced | B |
| A | | REPLACE RELATED PART WITH PART THAT HAS CORRECT PART NUMBER |
| B | | REPLACE ABSORBER CONTROL ECU |
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