Chevrolet Trax: DTC B2455 (RADIO): Cellular phone microphone

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 provide an overview of each diagnostic category.

DTC Descriptors

DTC B2455 01

Cellular Phone Microphone Circuit Short to Battery

DTC B2455 02

Cellular Phone Microphone Circuit Short to Ground

DTC B2455 04

Cellular Phone Microphone Circuit Open

Diagnostic Fault Information

Circuit/System Description

The radio provides the Cellular Phone Microphone with a supplied voltage on the Cellular Phone microphone high signal circuit. When the Microphone is in use, voice data from the user is sent back to the radio on the microphone low signal circuit.

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

B2455 01

• The radio detects a short to voltage in the low signal circuit for 10 seconds or greater.

B2455 02

• The radio detects a short to ground in the high signal circuit for 10 seconds or greater.

B2455 04

• The radio detects an open/high resistance in the high signal circuit for 10 seconds or greater.
• The radio detects an open/high resistance in the low signal circuit for 10 seconds or greater.

Action Taken When the DTC Sets

• The radio will not receive a signal from the Cellular Phone 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

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: It is necessary to have the vehicle in a quiet, open outside area where a cellular call can be successfully placed.

1. Ignition ON.
2. Verify that DTC B2455 is set.

If DTC B2455 is not set

All OK.

If DTC B2455 is set

3. Verify that your voice can be heard clearly after placing a cellular call.

If your voice can not be heard clearly

Refer to Circuit/System Testing.

If your voice can be heard clearly

4. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B24 Cellular Phone Microphone, ignition ON.
2. Test for 9.5-10.5 V between the signal circuit terminal B and ground.

If less than 9.5 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
2. Test for infinite resistance between the signal circuit and ground.

• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the A11 Radio.

If greater than 10.5 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the A11 Radio.

If between 9.5-10.5 V

3. Ignition ON.
4. Test for less than 1 V between the signal circuit terminal A and ground.

If greater than 1 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage in the circuit.
• If less than 1 V, replace the A11 Radio.

If less than 1 V

5. Test for 9.5-10.5 V between the signal circuit terminal B and the signal circuit terminal A.

If less than 9.5 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
2. Test for infinite resistance between the signal circuit terminal A and ground.

• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the signal circuit terminal A end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the vehicle A11 Radio.

If greater than 10.5 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
2. Test for less than 1 V between the signal circuit terminal A and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the A11 Radio.

If between 9.5-10.5 V

6. Test or replace the B24 Cellular Phone Microphone.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Mobile Telephone Microphone Replacement (Encore), Mobile Telephone Microphone Replacement (Trax)
• Control Module References for Radio replacement, programming and setup.

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