Trouble Shooting

WARNING: This page is about a different car, the 1997 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If problem is intermittent, check for faulty wiring and components by wiggling the wiring harnesses and components (DO NOT vigorously wiggle relays).

Ensure actuator cable is not too loose (may cause vehicle to lose speed when driving uphill) or too tight (causes high idle speed). Check for codes. See RETRIEVING CODES under SELF-DIAGNOSTIC SYSTEM. If code(s) are set, perform appropriate procedure under DTC TESTS . If no codes are set, go to DIAGNOSIS BY SYMPTOM table.
If it is suspected cruise control ECU is not receiving an input from a switch or speed sensor, check input signal circuits. See INPUT SIGNAL CIRCUITS under CIRCUIT TESTS. If problem is still present after all testing, replace cruise control ECU.

DIAGNOSIS BY SYMPTOM

Symptom

⁽¹⁾ TEST No.

Speed Cannot Be Set

No Codes Set (Normal Code)

10, ⁽²⁾, ⁽³⁾, 1, 6, 5, ⁽⁴⁾, ⁽⁶⁾, ⁽⁷⁾

Codes Cannot Be Displayed

8, ⁽⁷⁾ *

Unwanted Canceling

No Codes Set (Normal Code)

10, ⁽²⁾, ⁽³⁾, 1, 6, 5, ⁽⁴⁾, ⁽⁷⁾ *

Codes Cannot Be Displayed

8, ⁽⁷⁾ *

Actual Speed Differs From Set Speed

⁽⁶⁾, ⁽²⁾, 3, ⁽⁴⁾, 2, ⁽⁷⁾ *

Shifts Between 3rd Gear & Overdrive Uphill (Hunting)

3, ⁽⁷⁾ *

Speed Setting Does Not Cancel

When Clutch Pedal Is Pressed

⁽⁶⁾, 7, ⁽⁴⁾, ⁽⁷⁾ *

When Brake Pedal Is Pressed

⁽⁶⁾, 1, ⁽⁴⁾, ⁽⁷⁾ *

When Parking Brake Is Applied

5, ⁽⁴⁾, ⁽⁷⁾ *

When Shifting Into Neutral

⁽⁶⁾, 6, ⁽⁴⁾, ⁽⁷⁾ *

Cruise Control Switch Does Not Work

⁽³⁾, ⁽⁴⁾, ⁽⁷⁾ *

Speeds Less Than 25 MPH

Speed Can Be Set

⁽⁶⁾, ⁽²⁾, ⁽⁴⁾, ⁽⁷⁾ *

Speed Setting Does Not Cancel

⁽⁶⁾, ⁽²⁾, ⁽⁴⁾, ⁽⁷⁾ *

Poor Response In Accel & Resume

⁽⁶⁾, 3, ⁽⁴⁾, ⁽⁷⁾ *

Overdrive Does Not Resume ⁽⁵⁾

3, ⁽⁷⁾ *

Diagnostic Codes

Are Erased

9, ⁽⁷⁾ *

Cannot Be Displayed

11, ⁽⁷⁾ *

Are Displayed When Should Not Be

Cruise Indicator Light Stays On Or Does Not Come On

⁽¹⁾	See appropriate TEST under CIRCUIT TESTS .

⁽²⁾	Perform DTC TEST for Codes 21 and 23. See DTC TESTS .

⁽³⁾	Perform DTC TEST for Codes 32 and 34. See DTC TESTS .

⁽⁴⁾	Perform DTC TEST for Codes 11, 12 and 13. See DTC TESTS .

⁽⁵⁾	It is normal if the transmission is slow to resume overdrive (system is designed to operate like this). However, it should shift eventually.

⁽⁶⁾	Check cruise control cable. See ADJUSTMENTS .

⁽⁷⁾	Perform DTC TEST for Code 51. See DTC TESTS .