GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 XLR 🢒 Accessories 🢒 Navigation Systems 🢒 DTC B2474

Circuit Description

The backlighting error detection is determined inside the navigation radio. No external circuits are involved.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2474 Navigation Display Head (NDH) Backlighting Performance

Conditions for Running the DTC
    • The navigation radio checks for a backlighting internal error every 5 seconds during the following power modes:
       - ACC
       - ACC
       - ON
    • DTC B2474 does not set if DTC B1328 or DTC B1327 is current.

Conditions for Setting the DTC

A B2474 sets if any of the following conditions are present:

    • Backlighting circuit/bulb failure
    • Backlighting circuit current consumption is too high.
    • Backlighting heater is not providing heat.
    • The navigation radio temperature is over 105°C (221°F).

Action Taken When the DTC Sets

Any of the following may be observed:

    • Black screen and the audio and navigation functions cannot be controlled.
    • The screen brightness is incorrect.
    • Changes to the screen brightness are inconsistent.

Conditions for Clearing the DTC

The navigation radio determines that the backlighting fault is not present.

Diagnostic Aids

This DTC may be stored as a history DTC without affecting the operation of the navigation radio. If stored only as a history DTC and not a current DTC, do not replace the radio.

Test Description

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

  1. This step determines if the malfunction is present.

    2.

  2. This step verifies that the DTC sets under normal operating conditions.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF the ignition.
  2. Allow the navigation radio to cool for one hour.
  3. Turn ON the ignition with the engine OFF.
  4. Retrieve DTCs from the navigation radio.

Is B2474 a current DTC?

Go to Step 3

Go to Diagnostic System Check - Vehicle

3

Replace the navigation radio. Refer to Control Module References .

Did you complete the replacement?

Go to Step 4

--

4
  1. Use the scan tool in order to clear the DTC.
  2. Operate the vehicle according to the Conditions for Running the DTC in the supporting text.

Does the DTC reset?

Go to Step 2

System OK