Lexus IS250 · Service Manual CRUISE CONTROL SYSTEM

ROAD TEST

Troubleshooting

PROBLEM SYMPTOM CONFIRMATION

Inspect the SET function.
1. Turn the cruise control main switch on.
2. Drive at the required speed (40 km/h (25 mph) or higher).
3. Push the cruise control main switch to - (COAST)/SET.
4. After releasing the switch, check that the vehicle cruises at the set speed.

Inspect the ACCELERATION function.
1. Turn the cruise control main switch on.
2. Drive at the required speed (40 km/h (25 mph) or higher).
3. Push the cruise control main switch to - (COAST)/SET.
4. Check that vehicle speed increases while the cruise control main switch is pushed to + (ACCEL)/RES (RESUME), and that the vehicle cruises at the newly set speed when the switch is released.
5. Push the cruise control main switch to + (ACCEL)/RES (RESUME) and then release it immediately. Check that vehicle speed increases by approximately 1.6 km/h (1.0 mph) (tap-up control).

Inspect the - (COAST) function.
1. Turn the cruise control main switch on.
2. Drive at the required speed between 40 km/h (25 mph) and 200 km/h (125 mph).
3. Push the cruise control main switch to - (COAST)/SET.
4. Check that vehicle speed decreases while the cruise control main switch is pushed to - (COAST)/SET, and the vehicle cruises at the newly set speed when the switch is released.
5. Push the cruise control main switch to - (COAST)/SET, and then release it immediately. Check that vehicle speed decreases by approximately 1.6 km/h (1.0 mph) (tap-down control).

Inspect the CANCEL function.
1. Turn the cruise control main switch on.
2. Drive at the required speed between 40 km/h (25 mph) and 200 km/h (125 mph).
3. Push the cruise control main switch to - (COAST)/SET.
4. When performing any one of the following, check that the cruise control system is canceled and that the normal driving mode is reset.
  1. Depressing the brake pedal
  2. Depressing the clutch pedal
  3. The shift lever is moved from the D to the N position or the transmission is shifted to the 3rd, 2nd, or 1st gear with the shift lever in the S position
  4. Turning the cruise control main switch off
  5. Pulling the cruise control main switch to CANCEL

Inspect the RES (RESUME) function.
1. Turn the cruise control main switch on.
2. Drive at the required speed between 40 km/h (25 mph) and 200 km/h (125 mph).
3. Push the cruise control main switch to - (COAST)/SET.
4. Cancel the cruise control system by performing any of the above operations (other than turning the main switch off).
5. After pushing the cruise control main switch to + (ACCEL)/RES (RESUME) at a driving speed of more than 40 km/h (25 mph), check that the vehicle resumes the speed set prior to the cancellation.