GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Silhouette Ext. 🢒 Body and Accessories 🢒 Cruise Control 🢒 Cruise Control Inoperative

Step

Action

Value(s)

Yes

No

Important: : Perform the following steps in order to avoid misdiagnosis:

   • Inspect for proper operation of the following lamps:
      - The brake lamps
      - The CHMSL lamps
   • Inspect the throttle linkage for mechanical binding that may cause a system malfunction.
   • Test for a stored PCM Diagnostic Trouble Code (DTC).
        Refer to Diagnostic Trouble Code (DTC) List in Engine Controls.
   • Test for a stored Traction Control System (TCS) DTC.
        Refer to Diagnostic Trouble Code (DTC) List in Antilock Brakes.
The PCM will inhibit the cruise control when any of the following situations exist:
   • The vehicle speed is less than 25 mph.
   • The Park/Neutral Position Switch is placed into one of the following positions:
      - PARK
      - REVERSE
      - NEUTRAL
      - 1st GEAR
   • There are low engine RPMs.
   • There are high engine RPMs (fuel cut-off).
        Refer to Fuel System Diagnosis in Engine Controls for cruise control inhibit criteria diagnosis.

1
  1. Place the cruise control switch to the OFF position.
  2. Disconnect the cruise control module.
  3. Turn the ignition switch to the RUN position.
  4. Connect a test light between the cruise control module connector terminal F and ground.

Does the test light illuminate?

--

Go to Step 2

Go to Step 9

2

Connect a test light between the cruise control module terminal F and terminal E.

Does the test light illuminate?

--

Go to Step 3

Go to Step 10

3
  1. Place the cruise control switch in the ON position.
  2. Connect a test light between the cruise control module terminal E and terminal A.

Does the test light illuminate?

--

Go to Step 4

Go to Step 11

4

Connect a test light between the cruise control module connector terminal E and terminal B.

While observing the test light, press and hold the SET/COAST switch.

Does the test light illuminate?

--

Go to Step 5

Go to Step 12

5
  1. Connect a test light between the cruise control module connector between terminal E and terminal C.
  2. While observing the test light, press and hold the SET/COAST switch.

Does the test light illuminate?

--

Go to Step 13

Go to Step 6

6

Using a J 39200 Digital Multi-Meter (DMM), measure the voltage at the cruise control module connector between terminal D and terminal E.

Does the voltage measured equal the specified value?

B+

Go to Step 7

Go to Step 16

7

Connect a test light between the cruise control module connector between terminal E and terminal B.

Does the test light illuminate?

--

Go to Step 8

Go to Step 19

8
  1. Test CKT 84 for a short to B+.
  2. If CKT 84 is OK, replace the cruise control switch.

    3. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

System OK

--

9

Repair one of the following conditions in CKT 739, between the cruise control module connector terminal F and splice S266:

    • A poor connection
    • An open

Is the repair complete?

--

System OK

--

10

Repair the open in CKT 1150, between the cruise control module terminal E connector and G201.

Is the repair complete?

--

System OK

--

11
  1. Connect a test light between the cruise control module switch CKT 739 and the cruise control module connector terminal B.
  2. While observing the test light, press and hold the SET/COAST switch.

Does the test light illuminate?

--

Go to Step 15

Go to Step 14

12
  1. Test CKT 84 for one of the following conditions:
    2. • A short to ground
    • A poor connection
    • An open
  2. If CKT 84 is OK, replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

System OK

--

13
  1. Test CKT 87 for a short to CKT 84.
  2. If CKT 87 is OK, replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

System OK

--

14
  1. Test for one of the following conditions in CKT 739, between the cruise control switch and splice S266:
    2. • A poor connection
    • An open
  2. If CKT 739 is OK, replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

System OK

--

15
  1. Test CKT 397 for one of the following conditions:
    2. • A short to ground
    • A poor connection
    • An open
  2. If CKT 397 is OK, replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

System OK

--

16
  1. Disconnect the cruise control release (brake) switch connector.
  2. Using a J 39200 DMM, measure the voltage between the cruise control release (brake) switch connector terminal B and ground.

Does the measured voltage equal the specified value?

12V

Go to Step 18

Go to Step 17

17

Repair the open in CKT 739, between cruise control release switch and S266.

Is the repair complete?

--

System OK

--

18
  1. Test CKT 86 for one of the following conditions:
    2. • A poor connection
    • An open

    Important: Inspect the cruise control release (brake) switch for the proper alignment.

  2. If CKT 86 is OK, replace the cruise control release (brake) switch. Refer to Cruise Control Release Switch Replacement .

Is the repair complete?

--

System OK

--

19

Connect a test light between the cruise control module connector between terminal E and terminal C.

Does the test light illuminate?

--

Go to Step 25

Go to Step 20

20
  1. Set the park brake.
  2. Turn the ignition switch to RUN with the engine off.
  3. Raise the drive wheels.
  4. Use the J 39200 DMM in order to measure the voltage at the cruise control module connector between terminal K and ground.
  5. While observing the J 39200 DMM display, rotate the drive wheels by hand.

Does the voltage vary within the specified value?

0-5 volts

Go to Step 21

Go to Step 26

21
  1. Place the ignition switch in the OFF position.
  2. Test CKT 83 for one of the following conditions between the PCM and the cruise control module:
    3. • A poor connection
    • An open
  3. Reconnect the cruise control module connector.
  4. Attach a scan tool to the DLC.
  5. Start the engine.
  6. Clear and DTCs.
  7. Monitor the SMCC INHIBITED display on the scan tool .
  8. Attempt to operate the vehicle in cruise control mode.

Does the scan tool indicate SMCC INHIBITED?

--

Go to Step 27

Go to Step 22

22
  1. Clear any DTCs.
  2. Select Special Functions, then Engine Outputs, and then Cruise Inhibit on the scan tool .
  3. Use the scan tool in oder to command the SMCC to ALLOW cruise control.
  4. Use the J 39200 DMM in order to probe the cruise control module connector between terminal H and B+.

Does the measured value equal the specified value?

12V

Go to Step 23

Go to Step 24

23

Replace the cruise control module. Refer to Cruise Control Module Replacement .

Is the repair complete?

--

System OK

--

24
  1. Test CKT 83 for a short to ground.
  2. If CKT 83 is OK, service the PCM. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.

Is the repair complete?

--

System OK

--

25
  1. Test CKT 87 for a short to B+.
  2. If CKT 87 is OK, replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

System OK

--

26

Repair the open or the poor connection in CKT 389 between the cruise control module and the underhood accessory wiring junction block connector C2 terminal C8.

Is the repair complete?

--

System OK

--

27

Use the scan tool in order to monitor the following values in order to assure that the values are within the specified ranges:

    • The VSS signal
    • The trans range
    • The system voltage
    • The engine speed

Are the above values within the specified ranges?

VSS 25-100 mph

trans range 2nd, 3rd, or 4th gear

voltage 9-17 volts

engine speed 500-5400 rpm

Go to Step 28

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls

28

Service the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the repair complete?

--

System OK

--