PRE-RELEASE
DTC B125A
| DTC B125A |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
DTC B125A 02
Antenna Signal Circuit Short to Ground
DTC B125A 04
Antenna Signal Circuit Open
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
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Radio Antenna Signal
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B125A 02
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B125A 04
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1
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Ground
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1
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-
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1. May exhibit possible AM/FM interference.
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| Circuit/System Description |
The multi-band antenna is located on the roof of the vehicle. The radio antenna is enabled when the radio is turned on. The radio provides battery voltage to the antenna using the center conductor of the antenna coaxial cable. When a 12 V signal is seen on the center conductor of the antenna cable, both AM and FM signals are amplified.
| Conditions for Running the DTC |
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Ignition ON
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The battery voltage is between 9-16 V.
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| Conditions for Setting the DTC |
B125A 02
The radio detects a short to ground in the antenna signal circuit center conductor.B125A 04
The radio detects an open in the antenna signal circuit center conductor.| Action Taken When the DTC Sets |
Radio reception may be poor or not available.
| Conditions for Clearing the DTC |
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The condition responsible for setting the DTC no longer exists.
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A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.
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| 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
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
Ignition ON, radio ON, tune to a strong AM or FM station. Verify that the AM or FM reception is clear.
| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the radio antenna cable from the A11 Radio and from the radio antenna.
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| 2. |
Test for infinite resistance between the antenna cable center terminal and ground.
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| 3. |
If less than the specified value, replace the antenna cable.
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| 4. |
Test for less than 5 Ω on the antenna cable center circuit from end to end.
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| 5. |
If greater than the specified range, replace the antenna cable.
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| 6. |
Ignition ON, test for less than 1 V between the antenna cable center terminal and ground.
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| 7. |
If greater than the specified range, replace the antenna cable.
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| 8. |
Test for infinite resistance between the cable center terminal and the outer shield.
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| 9. |
If less than the specified value, replace the antenna cable.
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| 10. |
Connect the antenna cable to the A11 Radio. Test for 12-15 V between the antenna cable center terminal and ground at the radio antenna connector.
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| 11. |
If not within the specified range, replace the A11 Radio.
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| 12. |
If all circuits test normal, replace the radio antenna.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Radio Antenna Base Replacement
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Control Module References
for radio replacement, setup, and programming
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