Dtc C1756 Suspension Control Relay Malfunction

Suspension. Land Cruiser. Urj200, 202 Grj200 Vdj200
Suspension Control. Land Cruiser. Urj200, 202 Grj200 Vdj200

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT SUSPENSION CONTROL RELAY (AHC)

CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - ENGINE ROOM RELAY BLOCK AND BODY GROUND)

DTC C1756 Suspension Control Relay Malfunction


DESCRIPTION

This relay is to supply the power source to the pump and motor. The relay stays on while the height control is operated.

DTC Code
Detection Condition
Trouble Area
C1756
When either of the following is detected:
  1. With the suspension control relay not activated, an open signal of the suspension control relay is detected for 1 second or more.
  2. With the suspension control relay activated, a short signal of the suspension control relay is detected 8 times successively.
  1. Harness or connector
  2. Suspension control relay (AHC)
  3. Suspension control ECU

WIRING DIAGRAM


Land Cruiser. Urj200, 202 Grj200 Vdj200.Suspension Control.Suspension Control System. Dtc C1756 Suspension Control Relay Malfunction


INSPECTION PROCEDURE

NOTICE:
  1. Before performing troubleshooting, inspect the connectors of related circuits.
  2. If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed (Click here).
1.INSPECT SUSPENSION CONTROL RELAY (AHC)

  1. Remove the suspension control relay (AHC) from the engine room relay block.



    Land Cruiser. Urj200, 202 Grj200 Vdj200.Suspension Control.Suspension Control System. Dtc C1756 Suspension Control Relay Malfunction

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    3 - 5
    		Battery voltage is not applied to terminal 1 and 2
    		10 kΩ or higher
    Battery voltage is applied to terminal 1 and 2
    		Below 1 Ω


NG
REPLACE SUSPENSION CONTROL RELAY (AHC)
OK


2.CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - ENGINE ROOM RELAY BLOCK AND BODY GROUND)

  1. Remove the suspension control relay (AHC) from the engine room relay block.

  1. Disconnect the K36 suspension control ECU connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    K36-16 (RC) - Engine room relay block suspension control relay (AHC) terminal 1
    		Always
    		Below 1 Ω
    K36-16 (RC) or Engine room relay block suspension control relay (AHC) terminal 1 - Body ground
    		Always
    		10 kΩ or higher
    Engine room relay block suspension control relay (AHC) terminal 2 - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE SUSPENSION CONTROL ECU (Click here)