GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Astro - 4WD 🢒 DTC 🢒 DTC C0611

Circuit Description

The transfer case shift control module uses the VIN information for calculations that are required for the different calibrations used based on axle ratio, transmission, tire size, and engine. The system does not know which calibration to use without this information.

Conditions for Running the DTC
    • The transfer case shift control module is able to communicate via class 2 serial data.
    • The ignition is ON.
    • The system voltage is 9-16 volts.

Conditions for Setting the DTC

The transfer case shift control module does not receive a valid VIN digit for the correct application, K truck, L van or T truck within 2 seconds after power up.

Action Taken When the DTC Sets
    • The ignition counts since last fault is cleared.
    • The system is disabled until valid VIN data is received.
    • The SERVICE AWD indicator remains illuminated for the remainder of the ignition cycle.

Conditions for Clearing the DTC

A history DTC clears after a valid VIN digit is received.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests whether the condition is module, system or condition related.

    2.

  2. This step tests whether the condition has been corrected.

    3.

  3. This step replaces the transfer case shift control module.

Step

Action

Yes

No

Schematic Reference: Transfer Case Control Schematics

1

Did you perform the Diagnostic System Check - Transfer Case?

Go to Step 2

Go to Diagnostic System Check - Transfer Case

2
  1. Install a scan tool.
  2. Turn the ignition On.
  3. With a scan tool, monitor the DTC Information for DTC C0611 in the transfer case shift control module.

Does the scan tool indicate that DTC C0611 is current?

Go to Step 4

Go to Step 3

3

Since most occurrences of this DTC are caused by the installation of a new transfer case shift control module while the ignition is in the ON position, review the transfer case system or, with the customer to verify the conditions under which the DTC set.

Did vehicle operation cause this DTC to set?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

4
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within normal operating conditions.

Does the DTC reset?

Go to Step 5

System OK

5

Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement .

Did you complete the repair?

Go to Step 6

--

6
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK