GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 SLS 🢒 Engine 🢒 Cruise Control 🢒 Cruise Control Inoperative/Malfunctioning

Diagnostic Aids

The following are the correct switch resistance value range and readings displayed as the cruise control parameters when the switches are pressed one by one in the Body and Accessory/Cruise Control/IPM/Input Data List. If no switch is pressed, the resistance value should be infinite.

Switch Function

Resistance Value Range (Ω)

Counts

Mute/Gap (+)

1248-1292

204-243

Source/Gap (-)

1537-1591

174-203

If there is intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .

Step

Action

Values

Yes

No

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Cruise Control Connector End Views or Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Notice: Refer to Fastener Notice in the Preface section.

  1. Turn OFF the ignition switch.
  2. Disable the inflatable restraint steering wheel module. Refer to SIR Disabling and Enabling .
  3. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  4. Disconnect C277.
  5. Turn on the ignition switch, and do not start the engine.
  6. Connect a test lamp between the remote radio control head accessory supply voltage circuit and a good ground.

Does the test lamp illuminate?

--

Go to Step 3

Go to Step 7

3
  1. Turn OFF the ignition switch.
  2. With a DMM, measure the resistance between the remote radio control head accessory supply voltage circuit and the adaptive cruise control (ACC) gap adjustment/radio control signal circuit.
  3. While measuring the resistance, press and hold the Mute/Gap (+) steering wheel control switch.

Is the resistance measured within the specified value?

Off = O.L.

On = 7.8-8.6K Ω

Resume = 2.7-3.0K Ω

Set = 1.2-1.3K Ω

Go to Step 4

Go to Step 5

4

While measuring the resistance, press and hold the Source/Gap (-) steering wheel control switch.

Is the resistance measured within the specified value?

--

Go to Step 10

Go to Step 6

5

Test the ACC gap adjustment/radio control signal circuit between C277 and the instrument panel module (IPM) for the following:

    • Short to GND
    • An open circuit
    • An open circuit
    • High resistance
        Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

6

Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

7

Repair the following in the remote radio control head accessory supply voltage circuit:

    • An open circuit
    • Short to GND
    • High resistance

Refer to Circuit Testing and Wiring Repairs .

Is the repair complete?

--

Go to Step 10

--

8

Replace the Cruise Control switch. Refer to Turn Signal Multifunction Switch Replacement .

Have you finished the replacement?

--

Go to Step 10

--

9

Replace the body control module. Refer to Control Module References .

Have you finished the replacement?

--

Go to Step 10

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10

Operate the vehicle within the conditions for cruise control operation.

Is the cruise control system OK?

--

System OK

Go to Step 2