B128D

DTC B128D

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

DTC Descriptors
DTC B128D 62
- Video Display Position Signal Stuck Open

DTC B128D 63
- Video Display Position Signal Stuck Closed

Diagnostic Fault Information





Circuit/System Description

The radio controls the position of the Radio/Navigation Display via the position control circuit. When the UP position is desired, the radio sends a voltage signal to the Radio/Navigation Display actuator on the position control circuit, which commands the Radio/Navigation Display actuator to raise the display. When the display reaches the fully raised position, the actuator controller sends a voltage signal to the radio on the position signal circuit. When commanded up and fully raised, the voltage values on the control and position signal circuits will typically be greater than 4 V.

To lower the display, the radio removes the voltage signal on the position control circuit, which commands the Radio/Navigation Display actuator to lower the display. When the display reaches the fully lowered position, the actuator controller remove the voltage signal to the radio on the position signal circuit. When commanded down and fully lowered, the voltage values on the control and position signal circuits will be less than 1 V.

The display automatically returns to the lowered position when the ignition is turned OFF. When the ignition is turned ON, the radio commands the display to return to it's previous position, raised or lowered, that was commanded during the previous ignition cycle.

Conditions for Running the DTC

The radio is ON.

Conditions for Setting the DTC

DTC B128D 62

The radio has made 3 repeat requests to lower the display without receiving the correct signal from the actuator indicating the display reached the lowered position.

DTC B128D 63

The radio has made 3 repeat requests to raise the display without receiving the correct signal from the actuator indicating the display reached the raised position.

Action Taken When the DTC Sets

The radio cancels the raise or lower request and the display either does not move or returns automatically to it's previous position.

Conditions for Clearing the DTC

* A current DTC will clear when the conditions for setting are no longer present.
* A history DTC will clear after 100 malfunction free ignition cycles.

Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Radio/Audio System Description and Operation (Radio/Audio System)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Verification

Radio ON, press the NAV button on the Radio/HVAC control. The display should raise from a lowered position, or lower from the raised position and remain in that position.

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the Radio/HVAC display.
2. Reconnect the Radio/HVAC Control, if disconnected.
3. Test for less than less than 20 ohm between the ground circuit terminal 2 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

4. Test for 6kohm - 13.5kohm between the display position circuit terminal 5 and ground.

• If less than the specified range, test the circuit for a short to ground. If the circuit tests normal, replace the radio.
• If greater than the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the radio.

5. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Verify a test lamp illuminates between the remote enable circuit terminal 3 and ground.

• If the test lamp does not illuminate, test the enable circuit for an open/high resistance.

7. Test for less than 1 V between the display position signal circuit terminal 5 and ground.

• if greater than the specified range, test the position signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

8. Connect a DMM between the display control circuit terminal 4 and ground. Press and release the NAV button on the Radio/HVAC Control. Verify the voltage changes each time the display button is pressed. The value should change between less than 1 V to greater than 4 V.

• If the value is always less than 1 V, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
• If the value is always greater than 1 V, test the control circuit for a short to voltage. If the circuit tests normal replace the radio.

9. If all circuits test normal, replace the Radio/HVAC display actuator.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Radio, Video, Audio Disc Player, and Navigation Information Display Actuator Replacement (Radio, Video, Audio Disc Player, and Navigation Information Display Actuator Replacement)
* Control Module References (Programming and Relearning)for radio replacement, setup, and programming