DTC B2455
Diagnostic Instructions
DTC Descriptor
DTC B2455 00: Mobile Phone Microphone
Circuit
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Mobile Microphone Signal
|
B2455 00
|
B2455 00
|
B2455 00
|
-
|
Mobile Microphone Low Reference
|
-
|
B2455 00
|
1
|
-
|
1. OnStar Microphone Inoperative - Caller Cannot Be Heard
|
Circuit/System Description
The telematics communication interface control module provides
the mobile microphone with a supplied voltage on the mobile
microphone signal circuit. When the microphone is in use, voice
data from the user is sent back to the telematics communication
interface control module on the signal circuit. The telematics
communication interface control module provides a ground for the
microphone via the low reference wire.
Conditions for Running the DTC
• |
The ignition must be in the RUN or ACC
position. |
• |
The system voltage is at least 9.5 V and no
more than 15.5 V. |
• |
All the above conditions are present for greater
than 10 seconds. |
Conditions for Setting the DTC
• |
The telematics communication interface control
module detects an open, short to ground or short to voltage in the
mobile microphone signal circuit for 10 seconds or
greater. |
• |
The telematics communication interface control
module detects an open/high resistance in the low reference wire
circuit for 10 seconds or greater. |
Action Taken When the DTC Sets
• |
The OnStar® status LED turns red. |
• |
The telematics communication interface control
module will not receive a signal from the microphone. |
• |
Calls can be placed but the caller cannot be
heard. |
Conditions for Clearing the DTC
• |
The condition responsible for setting the DTC no
longer exists. |
• |
A history DTC will clear once 50 consecutive
malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Cellular Telephone Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cellular Telephone Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the
B24 mobile microphone.
- Test for less than 10 Ω between the low
reference circuit terminal 2 and ground.
⇒ |
If greater than the specified range, test the
circuit for an open/high resistance. |
- Ignition ON, test for 9.5-10.5 V between the
signal circuit terminal 3 and ground.
⇒ |
If less than the specified range, test the circuit
for a short to ground or an open/high resistance. If the circuit
tests normal, replace the K73 telematics communication interface
control module. |
⇒ |
If greater than the specified range, test the
circuit for a short to voltage. If the circuit tests normal,
replace the K73 telematics communication interface control
module. |
- If all circuits test normal, replace the B24 mobile
microphone.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|