Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Vehicle Identification Malfunction (C1789)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Suspension / Suspension Control / Adaptive Variable Suspension System / 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:

The vehicle identification information is not stored.
Vehicle identification information that is different from the stored information is received 3 times.

Vehicle identification information
ECM
CAN communication system
Absorber control ECU

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.
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:
- Symptom simulation.
  Click here
- DTC inspection.
  Click here
- Techstream inspection.
  Click here
  - If no malfunctions are found in other areas, replace the absorber control ECU.
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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Chassis > Air suspension > Trouble Codes

HINT:

If DTC C1781 (Suspension Control ECU Malfunction) 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

GO TO C1781

GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

2.	CHECK VEHICLE IDENTIFICATION INFORMATION STATUS

(a) Check that vehicle identification information has been stored.

Click here

Result	Proceed to
Information stored	A
Information not stored	B

PERFORM VEHICLE IDENTIFICATION INFORMATION REGISTRATION

3.	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.

Click here

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

REPLACE RELATED PART WITH PART THAT HAS CORRECT PART NUMBER

REPLACE ABSORBER CONTROL ECU

(Horizontality) G Sensor Malfunction (C1787)

Customize Parameters

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