ADAPTIVE VARIABLE SUSPENSION SYSTEM, Diagnostic DTC:C1789

DTC Code	DTC Name
C1789	Vehicle Identification Malfunction

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 power management control ECU or steering sensor 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: The vehicle identification information is not stored. Vehicle identification information that is different from the stored information has been received 3 times.	CAN communication system Vehicle identification information Power management control ECU Steering sensor Absorber control ECU	Does not come on

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

C1789

Vehicle Identification Malfunction

Either condition is met:

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

CAN communication system
Vehicle identification information
Power management control ECU
Steering sensor
Absorber control ECU

Does not come on

CAUTION / NOTICE / HINT

Note

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) GTS inspection (ECU Data List or Active Test Click here). 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

CHECK FOR DTC (CAN COMMUNICATION SYSTEM)

Check for DTCs.

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Chassis > Air suspension > Trouble Codes

Result

Result	Proceed to
CAN DTC is not output	A
CAN DTC is output	B

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

CHECK VEHICLE IDENTIFICATION INFORMATION STATUS

Check that vehicle identification information has been stored.

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Result

Result	Proceed to
Information stored	A
Information not stored	B

PERFORM VEHICLE IDENTIFICATION INFORMATION REGISTRATION Click here

CHECK RELATED PART

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	Power management control ECU
	Steering sensor

Note

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 power management control ECU.

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Refer to the following procedures to remove the steering sensor.

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Tech Tips

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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Result

Proceed to
NEXT

CHECK FOR DTC

Clear the DTCs.

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Chassis > Air suspension > Clear DTCs
Turn the power switch off.

Check if DTC C1789 is output.

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Chassis > Air suspension > Trouble Codes

OK
DTC C1789 is not output.

Result

Proceed to
OK
NG

END

REPLACE ABSORBER CONTROL ECU Click here