A.D.D. Control System: Inspection

WARNING: This page is about a different car, the 2002 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

First judge that the malfunction is found in A.D.D. control system or in 2 - 4 selector system. See TOUCH SELECT 2-4 SWITCH (4RUNNER) .

Inspect clutch hub and clutch sleeve :
1. Check the wear and damage of the clutch hub and clutch sleeve.
  
  Fig 1: Inspecting Clutch Hub & Sleeve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  If necessary, replace them.
2. Check that clutch sleeve slides smoothly on the clutch hub.
Using a feeler gauge, Measure clearance of sleeve fork and clutch sleeve

Fig 2: Measuring Clutch Sleeve To Fork Clearance
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Maximum clearance: 0.35 mm (0.0138 in.)
If the clearance exceeds the maximum, replace the fork or sleeve
Inspect A.D.D. actuator :
1. Disconnect the actuator connector.
2. Measure the resistance between the terminals 2 and 6.
  1. Standard resistance: 0.3 -100 MΩ
3. Measure the resistance between the terminals 2 or 6 and body ground.
  1. Standard resistance: More than 0.5 MΩ
  If the resistance value is not as specified, replace the actuator assembly.
Inspect A.D.D. actuator operation :
Apply battery positive voltage between the terminal 2 or 6, and check the actuator operation by sound, A.D.D. status and continuity between the terminal 3 and 4.

Fig 3: Identifying A.D.D. Actuator Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: A.D.D. Actuator Terminal Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If the operation is not as specified, replace the actuator assembly.
Inspect A.D.D. relay :
1. Check the continuity between each terminal, as shown in the chart.
  
  Fig 5: Identifying A.D.D. Relay Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 6: A.D.D. Relay Terminal Specifications Chart (2 Of 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Apply battery positive voltage between each terminal and check the continuity between each terminal, as shown in the chart.
If continuity is not as specified, replace the relay.

Fig 7: A.D.D. Relay Terminal Specifications Chart (2 Of 2)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect transfer 4WD position switch. See DIAGNOSIS in TRANSFER CASE under TRANSAXLE/TRANSMISSION.
Remove A.D.D. actuator. See A.D.D. CONTROL SYSTEM .
Inspect clutch hub and clutch sleeve :
Check the clutch hub and clutch sleeve for wear and damage. If necessary, replace them.