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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Grand Prix 🢒 DTC 🢒 DTC B3621

DTC B3621

The HUD detects that the HUD Info Down signal circuit is low for greater than 15 seconds.

Circuit Description

The HUD monitors the switch signal circuits in order to perform various functions. The HUD switch contains 3 active low momentary switches, and a variable resistor. The HUD detects a switch activation when the signal circuit is active.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The HUD detects that the HUD Info Down signal circuit is low for greater than 15 seconds.

Action Taken When the DTC Sets

The HUD ignores the malfunctioning switch circuit.

Conditions for Clearing the DTC
    • The current DTC becomes history when the fault is no longer present.
    • The history DTC clears after 40 malfunction free ignition cycles.
    • The HUD receives a clear code command from the scan tool.

Step

Action

Yes

No

Schematic Reference: Head Up Display Schematics

1

Did you review the operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Instrument Panel, Gages and Console

2
  1. Turn ON the ignition, with the engine ON.
  2. Adjust the head up display (HUD) UP, then DOWN.

Does the HUD display adjust properly?

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

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Disconnect the HUD.
  3. Connect a test lamp between the DOWN control circuit and ground. Refer to Circuit Testing in Wiring Systems.
  4. Move the HUD up/down switch to the DOWN position.

Does the test lamp illuminate?

Go to Step 7

Go to Step 4

4

Test the HUD DOWN control circuit for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the HUD switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

Replace the HUD switch. Refer to Head Up Display Switch Replacement .

Did you complete the replacement?

Go to Step 9

--

7

Inspect for poor connections at the harness connector of the HUD. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

8

Replace the HUD. Refer to Instrument Cluster Head Up Display Replacement .

Did you complete the replacement?

Go to Step 9

--

9
  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?

System OK

Go to Step 2