DTC B186C
Cellular, Entertainment, and Navigation | Diagnostic Information and Procedures | Document ID: 5483683 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 provides an overview of each diagnostic category. DTC Descriptors DTC B186C 11 Amplifier Control Signal Circuit Short to Ground DTC B186C 13 Amplifier Control Signal Circuit Open Diagnostic Fault Information
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performanc |
|---|---|---|---|---|
| 6978 | DTC B186C 11 | DTC B186C 13 | — | — |
Circuit/System Description The amplifier control circuit provides varying pulse width modulated (PWM) signals to control overall muting of the amplifier. The PWM signals are varying duty cycle percentages ranging from 0–100 percent. A low duty cycle unmutes all amplifier channels and a high duty cycle mutes all amplifier channels. The amplifier control circuit will measure less than 1 V when the mute function is OFF, and approximately 8 V DC when at full mute. The A11 Radio monitors the amp control circuit for faults. Conditions for Running the DTC The following are conditions that must be present in order for the radio to enable the diagnostics. The radio is in ACCESSORY, RUN, or RAP power mode. The system voltage is 9–16 V. The radio performs the test once during wake up. Conditions for Setting the DTC B186C 11 Circuit 6978 is shorted to ground for 5 s or greater B186C 13 Circuit 6978 has an open or high resistance 5 s Action Taken When the DTC Sets Radio sets the DTC and continues to output correct state. Conditions for Clearing the DTC The condition must be corrected. A history DTC clears after 100 malfunction-free ignition cycles. Reference Information Schematic Reference Radio/Navigation System Schematics Connector End View Reference Master Electrical Component List Description and Operation Radio/Audio System Description and Operation 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 Testing
- Ignition OFF, disconnect the X2 harness connector at the T3 Audio Amplifier. Ignition ON, A11 Radio ON, mute ON.
- Test for 7.5–8.5 V between the control circuit terminal 14 and ground. ⇒ If greater than 8.5 V 2.1. Ignition OFF, disconnect the X2 harness connector at the A11 Radio. Ignition ON. 2.2. Test for less than 1 V between the control 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 less than 7.5 V 2.1. Ignition OFF, disconnect the X2 harness connector at the A11 Radio. 2.2. Test for infinite resistance between the control circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 2.3. Test for less than 2 Ω in the control circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the A11 Radio. ⇓ If between 7.5–8.5 V
- A11 Radio ON, mute OFF.
- Test for less than 1 V between the control circuit terminal 14 and ground. ⇒ If 1 V or greater Replace the A11 Radio. ⇓ If less than 1 V
- Test or replace the T3 Audio Amplifier. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Control Module References for radio or audio amplifier replacement, programming, and setup.