Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminal CCS of ECM connector and body ground.
PREPARATION:
1. Remove the ECM with connector being connected.
2. Turn ignition switch ON.
Fig 1: Checking Voltage Between Terminal CCS Of ECM Connector And Body Ground
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK:

Measure voltage between terminal CCS of ECM connector and body ground, when each of the -/SET, +/RES and CANCEL is turned ON.

OK:

Fig 2: Voltage Reference Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: Proceed to next circuit inspection shown on problem symptom table (See PROBLEM SYMPTOMS TABLE ).
2. NG: Go to Next Step
Check main switch continuity.
PREPARATION:
1. Remove steering wheel center pad (See STEERING WHEEL ).
2. Disconnect the control switch connector.
Fig 3: Checking Main Switch Continuity
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK:
1. Measure resistance between terminals 4 and 5 of cruise control switch connector when control switch is operated.
  
  Fig 4: Resistance Reference Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check continuity between terminal 4 and 5 of the control switch connector when the main switch is held on and off.
OK:

Fig 5: Switch Position Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Replace control switch.
2. OK: Go to next step
Check harness and connector between ECM and cruise control switch, cruise control switch and body ground (See HOW TO PROCEED WITH TROUBLESHOOTING ).
1. NG: Repair or replace harness or connector.
2. OK: Go to next step
Check cruise control indicator light (See combination meter.)
1. NG: Replace combination meter.
2. OK: Check and replace ECM (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).