Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC B3621: Head-Up Display (HUD) Down Switch Circuit Short to GroundDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
HUD Battery+ | 1 | 1 | -- |
HUD Ground | -- | 1 | 1 |
HUD Page Switch Signal | B3619 | 1 | 1 |
HUD Up Switch Signal | B3620 | 1 | 1 |
HUD Down Switch Signal | B3621 | 1 | 1 |
HUD Dimming Up switch Signal | B3634 | 1 | 1 |
HUD Dimming Down Switch Signal | B3659 | 1 | 1 |
HUD Mode Switch Signal | B3744 | 1 | 1 |
HUD Switch Ground | -- | 1 | 1 |
1. Head- up Display (HUD) Malfunction. | |||
Circuit/System Description
The head-up display (HUD) image down switch is used to vertically adjust the HUD image on the windshield to accommodate various vehicle operator heights. The HUD monitors the image down switch signal circuit in order to adjust image positions. When the HUD image down switch is depressed and the ignition is in the RUN position, the switch signal to the HUD is low.
Conditions for Running the DTC
The ignition is in RUN.
Conditions for Setting the DTC
The HUD detects that the HUD image down switch signal circuit is low for greater than 60 seconds.
Action Taken When the DTC Sets
The HUD ignores the malfunctioning switch circuit.
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction-free warm-up cycles. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Head Up Display (HUD) Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
Ignition ON, verify that when the HUD image down switch is pressed and released the HUD scan tool Adjust Display Down Switch parameter toggles between Active and Inactive.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the HUD switch.
- Test for less than 5.0 ohms between the HUD switch ground circuit terminal F and ground.
- Ignition ON, verify the scan tool Adjust Display Down Switch parameter is Inactive.
- Install a 3A fused jumper wire between the signal circuit terminal K and ground. Verify the scan tool Adjust Display Down Switch parameter is Active.
- If all circuits test normal, test or replace the HUD switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If not Inactive, test the signal circuit terminal K for a short to ground. If the circuit tests normal, replace the HUD. |
| ⇒ | If not Active, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HUD. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
