DTC B1278 or B1279
Diagnostic Instructions
DTC Descriptors
| DTC B1278 01: Left Auxiliary Input Signal
Circuit Short to Battery |
| DTC B1278 02: Left Auxiliary Input Signal
Circuit Short to Ground |
| DTC B1279 01: Right Auxiliary Input
Signal Circuit Short to Battery |
| DTC B1279 02: Right Auxiliary Input
Signal Circuit Short to Ground |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
B+
|
-
|
4
|
-
|
-
|
Detection Signal Circuit
|
4
|
5
|
5
|
-
|
Left Audio Signal Terminal 12
|
B1278 02, 3
|
3
|
B1278 01, 3
|
-
|
Left Audio Signal Terminal 14
|
3
|
3
|
3
|
-
|
Right Audio Signal Terminal 13
|
B1279 02, 2
|
2
|
B1279 01, 2
|
-
|
Right Audio Signal Terminal 15
|
2
|
2
|
2
|
-
|
Audio Common Circuit
|
-
|
1
|
-
|
-
|
Ground
|
-
|
4
|
-
|
-
|
1. No or distorted audio from both sides
2. No or distorted right side audio
3. No or distorted left side audio
4. External audio inputs inoperative
5. AUX selection always available with or without device
connected
|
|
| |
Circuit/System Description
A remote 3.5 mm auxiliary stereo jack allows playback of
audio signals from remote devices (e.g., laptop computer, IPOD, MP3
player, etc.). The auxiliary audio jack has an internal mechanical
detection switch. The switch is normally closed, connecting the
detection circuit to the audio common circuit. When a device is
inserted to the auxiliary audio jack, the switch opens and the
multimedia player interface module detects a high voltage on the
detection circuit. A serial data message is sent to the radio, the
radio will switch to AUX as the audio source. The multimedia player
interface module receives the analog audio signals from the
connected device and sends the signals to the radio.
Conditions for Running the DTC
| • |
Ignition in RUN or ACC
position. |
| • |
The system voltage is at least
9.5 V and no more than 15.5 V. |
| • |
The multimedia player
interface module detects a device has been connected to the
auxiliary audio input jack. |
Conditions for Setting the DTC
B1278 01, B1279 01
| • |
The multimedia player
interface module detects a short to battery on either of the audio
signal circuits from the auxiliary audio jack. |
| • |
The condition is present for
greater than 250 mS. |
B1278 02, B1279 02
| • |
The multimedia player
interface module detects a short to ground on either of the audio
signal circuits from the auxiliary audio jack. |
| • |
The condition is present for
greater than 250 mS. |
Action Taken When the DTC Sets
No or reduced audio is heard from the remote audio device.
Conditions for Clearing the DTC
| • |
The conditions for setting the
DTC are no longer present on the auxiliary input signal
circuits. |
| • |
A history DTC clears after 50
malfunction-free ignition cycles. |
Diagnostic Aids
| • |
Playback of an audio device
that is connected to the 3.5 mm jack can only be controlled
using the controls on the device. |
| • |
The volume control on the
device may need to be adjusted to ensure sufficient playback volume
through the infotainment system. |
| • |
This DTC may be stored as a
history DTC without affecting the operation of the module.
|
| • |
If stored only as a history
DTC and not retrieved as a current DTC, do not replace the
module. |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
X1 harness connector at the X83 auxiliary audio input. |
| 2. |
Ignition ON, test for less
than 1 V between the terminals listed below and ground:
|
| ⇒ |
If greater than the specified value, test the
circuit for a short to voltage. If the circuit tests normal,
replace the T11 multimedia player interface module. |
| 3. |
Ignition OFF, test for
infinite resistance between the terminals listed below and
ground: |
| ⇒ |
If less than the specified value, test the circuit
for a short to ground. If the circuit tests normal, replace the T11
multimedia player interface module. |
| 4. |
If all of the circuits test
normal, replace the X83 auxiliary audio input. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References multimedia player interface module
replacement, setup, and programming
|
