Inspection Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch ON and turn the tester ON.
3. Select the item below in the Data List, and read the value displayed on the Techstream.

   Body Electrical / Combination Meter / Data List: 

   BODY ELECTRICAL / COMBINATION METER / DATA LIST
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Rheostat Value (A/D)	Light control rheostat switch / Min.: 0, Max.: 255	Light brightness changes within specified range: Dark (0) to bright (255)	-

   OK: 

   Light brightness can be changed within the specified range by actual operation. 

NG: Go to step 2 

OK: REPLACE COMBINATION METER ASSEMBLY 

1. Remove the GAUGE fuse from the main body ECU.
2. Measure the resistance.

   Standard resistance: 

   Below 1 Ω 

3. Reinstall the GAUGE fuse.

NG: REPLACE FUSE 

OK: Go to Next Step 

1. Disconnect the D29 light control rheostat connector.
2. Measure the voltage.

   Standard voltage 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester Connection	Condition	Specified Condition
   D29-10 - Body ground	Ignition switch ON	11 to 14 V

   Fig 1: Identifying Light Control Rheostat Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Reconnect the light control rheostat connector.

OK:  Go to step  5

NG: Go to Next Step 

1. Disconnect the D29 light control rheostat connector.
2. Disconnect the 4P main body ECU connector.
3. Measure the resistance.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester	Condition	Specified Condition
   D29-10 (IG) - 4P-1	Always	Below 1 Ω

   Fig 2: Identifying Main Body ECU And Light Control Rheostat Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the light control rheostat connector.
5. Reconnect the main body ECU connector.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to Next Step 

1. Remove the light control rheostat but without disconnecting the connector.
2. Turn the ignition switch ON.
3. Using an oscilloscope, check the signal waveform of the light control rheostat.
   WAVEFORM REFERENCE
   
   

   Item	Contents
   Terminal connection	D29-2 (RV) - Body ground
   Tool setting	5V / DIV, 50ms / DIV
   Vehicle condition	Ignition switch ON

   Fig 3: Identifying Light Control Rheostat Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: 

   Waveform is as shown in  Fig 3 . 

   HINT:

   Duty ratio changes as the illumination dims. (A becomes longer)

4. Reinstall the light control rheostat.

NG: REPLACE LIGHT CONTROL RHEOSTAT 

OK: Go to Next Step 

1. Disconnect the D1 combination meter assembly connector.
2. Disconnect the D29 light control rheostat connector.
3. Measure the resistance.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   D1-7 (ILL-) - D29-2 (RV)	Below 1 Ω

   Fig 4: Identifying Combination Meter Assembly And Light Control Rheostat Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the combination meter assembly.
5. Reconnect the light control rheostat connector.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: REPLACE COMBINATION METER ASSEMBLY