*CHECKING THE SPEED CONTROL OPERATION

For a complete wiring diagram Refer to Section 8W

Possible Causes

BRAKE SWITCH SIGNAL

CHECKING CRUISE SWITCHES

CHECKING THE ECM FOR DTC'S

ENGINE CONTROL MODULE

VSS SIGNAL

Diagnostic Test

1.CHECKING THE ECM FOR DTC'S

Are there any ECM DTCs present?

Yes

Refer to symptom list for problems related to the ECM DTC.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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2.CHECKING CRUISE SWITCHES

NOTE: Pressing each cruise button should result in the following voltages: ON/OFF 0.78v - 0.98, SET 3.26 - 3.46v, RESUME/ACCEL 3.93 - 4.13v, CANCEL 1.67 - 1.87v, COAST 2.64 - 2.84v, No Button Pressed 4.44 - 4.64v

NOTE: Pressing each cruise button should result in the following voltages: ON/OFF 3.62 - 3.82v, SET 1.25 - 1.45v, RESUME/ACCEL 2.13 - 2.33v, CANCEL 2.93 - 3.13v, COAST 0.78 - 0.98v, No Button Pressed 4.44 - 4.64v

Does each switch provide the correct voltage?

Yes

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Check S/C Switch signal and Ground circuits. If o.k., replace the S/C Switches.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

3.VERIFY S/C OPERATION

NOTE: Prior to testing the speed control operation, ensure the Learn Speed Control feature has been performed on the ECM.

Does the Speed Control function properly?

Yes

Test Complete.

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4.VSS SIGNAL

Is the scan tool displaying an accurate vehicle speed?

Yes

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Refer to symptom list for problems related to the Vehicle Speed Sensor.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

5.BRAKE SWITCH SIGNAL

Did the scan tool indicate the correct brake pedal state when pressing and releasing the Brake Pedal?

Yes
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

No

Refer to symptom list for problems related to Brake Switch Signal.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).