DEFINITION: Cruise control does not engage when driving the vehicle over 25 mph (40 km/h) and the Set/Accel switch is pressed and released at the stalk mounted lever.

Did you perform the Cruise Control System Check?

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Go to Step 2

Go to Cruise Control System Check

1. Install a scan tool.
2. Establish communications with the engine control module (ECM).
3. Select DTC information.

Is a DTC P0571 set as current?

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Go to Step 3

Go to Step 4

Refer to the Engine Controls section to repair this DTC.

Is the repair complete?

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Go to Cruise Control System Check

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1. Ignition ON, with the engine OFF.
2. With the scan tool, observe the CRUISE SWITCH parameter in the ECM data list.

Does the scan tool display ON?

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Go to Step 5

Go to Step 6

1. Observe the SET SWITCH parameter.
2. Press the SET/ACCEL button at the end of the lever.

Does the scan tool display ON?

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Go to Step 7

Go to Step 8

Remove and inspect the CRUISE fuse for an open.

Is the fuse open?

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Go to Step 9

Go to Step 10

1. Observe the BRAKE LIGHT SWITCH parameter.
2. Apply the brake pedal.

Does the scan tool display APPLIED?

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Go to Step 11

Go to Step 12

1. Turn OFF the ignition.
2. Disconnect ECM connector C2.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage at ECM connector C2 terminal 43 with the SET/ACCEL button at the end of the lever pressed.

Does the voltage measure near the specified value?

10-12 V

Go to Step 11

Go to Step 14

Locate and repair the short to ground or voltage.

Did you find and correct the condition?

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Go to Step 13

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1. Turn OFF the ignition.
2. Disconnect ECM connector C2.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage at ECM connector C2 terminal 42.

Does the voltage measure near the specified value?

10-12 V

Go to Step 11

Go to Step 15

Replace the ECM.

Is the replacement complete?

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Go to Step 13

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Verify that the brake lamps illuminate when applying the brake pedal.

Do the brake lamps illuminate when applying the brake pedal?

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Go to Step 16

Go to Step 17

Verify that the cruise control operates properly.

Does the cruise control operate properly?

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Go to Cruise Control System Check

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Test CKT FB300 for an open circuit.

Did you find and correct the condition?

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Go to Step 13

Go to Step 21

1. Disconnect the cruise control switch connector.
2. Turn ON the ignition, with the engine OFF.
3. Measure the voltage at the cruise control switch connector terminal B.

Does the voltage measure within the specified range?

10-12 V

Go to Step 18

Go to Step 19

1. Disconnect ECM connector C2.
2. Measure the voltage at terminal 27 with the brake pedal applied.

Does the voltage measure within the specified range?

10-12 V

Go to Step 11

Go to Step 20

Test the following components or circuits for proper operation:

Did you find and correct any of the above conditions?

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Go to Step 13

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Test CKT FA300 for an open circuit.

Did you find and correct the condition?

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Go to Step 13

Go to Step 21

Test the voltage input circuit (BRN wire) to the cruise control switch for an open.

Did you find and correct the condition?

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Go to Step 13

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Test CKT FB500 for an open circuit.

Did you find and correct the condition?

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Go to Step 13

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Replace the cruise control switch.

Is the replacement complete?

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Go to Step 13

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