DTC C1741/41: Air Suspension Relay Circuit: Procedure

1. Check DTCs. Refer to DTC CHECK / CLEAR .
   1. Confirm if the DTC C1761/61 and/or C1774/74 is recorded.

      OK

      DTC C1761/61 and/or C1774/74 is not output.

      HINT: 

      If either DTCC1761/61 (ECU malfunction). Refer to DTC C1761/61: ECU Malfunction  or C1774/74 (power source circuit). Refer to DTC C1774/74: Power Source Circuit  is displayed, carry out the necessary inspection. If they are output at the same time, carry out the necessary inspection for DTC C1774/74 first.

NG → REPAIR CIRCUIT INDICATED BY OUTPUT CODE 

OK: Go to next step 

HINT: 

When not using Techstream, go to step  3.

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to the ON position, and push the Techstream main switch ON.
3. Select the item below in the ACTIVE TEST, and operate it with the Techstream.

   Air suspension

   Item	Vehicle Condition / Test Details	Diagnostic Note
   Motor Relay	AIR SUS relay / ON or OFF	-

4. Check the operation sound of the AIR SUS relay when operating it with the Techstream.

   OK

   The operation sound of the AIR SUS relay can be head.

NG → Go to next step 

OK → REPLACE SUSPENSION CONTROL ECU 

1. Remove the AIR SUS relay from the engine room R/B.
   Fig 1: Identifying Air SUS Relay

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the values in the table below.

   Standard resistance

   Tester Connection	Specified Condition
   3 - 5	10 kΩ higher
   	Below 1 Ω (When battery voltage is applied to terminals 1 and 2)

NG → REPLACE AIR SUS RELAY 

OK: Go to next step 

1. Disconnect the suspension control ECU S14 connector.
   Fig 2: Identifying Suspension Control ECU S14 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the values in the table below.

   Standard resistance

   Tester Connection	Specified Condition
   S14-18 (RC) - 1 (for AIR SUS relay)	Below 1 Ω
   S14-18 (RC) - Body ground	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Measure the resistance according to the values in the table below.
   Fig 3: Identifying AIR SUS Relay Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance

   Tester Connection	Specified Condition
   2 (for AIR SUS relay) - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE SUSPENSION CONTROL ECU