Trouble Shooting

NOTE: If problem is intermittent, check for faulty wiring and components by wiggling 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 any codes are set, perform appropriate procedure under DIAGNOSTIC 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⁽¹⁾

Symptom

Circuit Test No.

Speed Cannot Be Set Or Unwanted Canceling

No Codes Are Set (Normal Code) ⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾

7, 1, 4,

Codes Cannot Be Displayed ⁽⁶⁾

Actual Speed Differs From Set Speed ⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾⁽⁸⁾

Shifts Between 3rd Gear & Overdrive Uphill (Hunting) ⁽⁶⁾

Speed Setting Does Not Cancel

When Brake Pedal Is Pressed ⁽⁴⁾⁽⁵⁾⁽⁶⁾

When Shifting Into Neutral ⁽⁴⁾⁽⁵⁾⁽⁶⁾

Cruise Control Switch Does Not Work

⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾

At Speeds Less Than 25 MPH (40 KPH) Speed Can Be Set Or Speed Setting Does Not Cancel

⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽⁷⁾

Poor Response In Accel & Resume ⁽⁴⁾⁽⁵⁾⁽⁶⁾

Overdrive Does Not Resume ⁽⁶⁾⁽⁹⁾

Diagnostic Codes

Are Erased ⁽⁶⁾

Cannot Be Displayed Or Are Displayed When Should Not Be ⁽⁶⁾

Cruise Indicator Light Stays On Or Will Not Come On

⁽¹⁾	See appropriate TEST under CIRCUIT TESTS .

⁽²⁾	See DTC 21 under DIAGNOSTIC TESTS.

⁽³⁾	See DTC 32 under DIAGNOSTIC TESTS.

⁽⁴⁾	See DTC 11 OR 15 under DIAGNOSTIC TESTS.

⁽⁵⁾	Check cruise control cable. See ADJUSTMENTS .

⁽⁶⁾	Check Cruise Control ECU input. See PIN VOLTAGE TESTS .

⁽⁷⁾	See DTC 23 under DIAGNOSTIC TESTS

⁽⁸⁾	See DTC 51 under DIAGNOSTIC TESTS

⁽⁹⁾	It is normal if the transmission is slow to resume overdrive (system is designed to operate like this). However, it should shift eventually.