B1578 on 2024-2026 Dodge Charger: Audio Antenna Circuit Fault Explained

What's Unique About the 2024-2026 Dodge CHARGER

For the new generation of Dodge Charger (2024-2026) built on the STLA Large platform, this code has a unique history documented by the manufacturer. Dodge has issued technical service bulletins (TSBs) advising technicians that this code may be stored in the radio's memory without any actual fault or customer-facing symptom like poor reception. The official guidance is to not perform any diagnosis or repair for an active or stored B1578 code unless the vehicle owner is actually experiencing a problem with the audio system. This suggests the code can be triggered spuriously by a software anomaly, a common theme with the new Uconnect 5 systems which have been subject to class-action lawsuits for general unreliability.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Poor or no AM/FM radio reception
• Radio static is more prevalent than usual
• No noticeable symptoms (as noted in TSB #9100747 and #S258A000026)

Most Likely Causes

1. Spurious Code / Software Anomaly 🔴 High Probability Manufacturer TSBs #9100747 and #S258A000026 both indicate the code can be present without a customer complaint, and advise against diagnosis in such cases. This strongly implies a known issue where the code can be set without a real hardware fault. The Uconnect 5 system used in these vehicles is known for various software-related glitches.
   How to confirm: Check if radio reception is normal. If there are no audio issues, the code is likely spurious. A simple reset by disconnecting the battery for a few minutes may clear it.
   Typical fix: Clear the code with a scan tool. If there are no symptoms, no further action is needed per the manufacturer's recommendation. A future radio software update may permanently resolve the spurious code.
   Est. part cost: $0
2. Shorted Antenna Coaxial Cable 🟡 Medium Probability The coaxial cable runs from the radio to the antenna, often through the vehicle's pillars and headliner. It can be pinched, chafed, or damaged during assembly or from vibrations, causing the center conductor to short to the outer shield (ground).
   How to confirm: Disconnect the cable from both the radio and the antenna base. Use a multimeter set to resistance (Ohms) to check for continuity between the center pin and the outer metal connector. 🎬 Watch: How to test an antenna cable with a multimeter. A reading of low resistance (near zero ohms) indicates a short.
   Typical fix: Replace the damaged antenna cable. In some cases, a special diagnostic kit (Miller tool 9977-6) is used by dealers to pinpoint the short.
   Est. part cost: $50-$150
3. Faulty Antenna Base/Amplifier ⚪ Low Probability The 'shark fin' antenna base on the roof often contains a small amplifier to boost the signal. This amplifier can fail internally due to moisture intrusion or manufacturing defects and develop a short circuit.
   How to confirm: After confirming the coaxial cable is not shorted, the antenna base is the next likely component. Diagnosis often involves substituting it with a known-good part. This is a common failure point on related Stellantis vehicles.
   Typical fix: Replace the antenna assembly. This involves lowering the rear of the headliner to access 🎬 See how to remove and unplug a shark fin antenna. the mounting nut and cable connectors.
   Est. part cost: $100-$250
4. Radio Head Unit Internal Fault ⚪ Low Probability While less common, the receiver circuitry inside the Uconnect radio itself can fail, causing it to incorrectly report a short in the antenna circuit. These head units have been the subject of owner complaints for various malfunctions.
   How to confirm: This is typically diagnosed by exclusion. If the antenna and its cable are confirmed to be good, the fault lies with the radio head unit. The dealer may attempt a software update first before recommending replacement.
   Typical fix: Replace or repair the radio head unit.
   Est. part cost: $500-$2000+

Diagnosis Steps

1. Verify the symptom. Is there an actual problem with AM/FM radio reception?
2. If there are no reception issues, do not proceed with diagnosis, per manufacturer TSB #9100747. The code is likely spurious. Clear the code and see if it returns.
3. If reception is poor, turn the radio off and disconnect the antenna cable from the back of the radio unit.
4. Using a multimeter, measure the resistance between the center pin and the outer conductor of the disconnected antenna cable. A low resistance reading (near zero ohms) confirms a short circuit in the cable or antenna assembly.
5. To isolate the fault, disconnect the cable from the antenna base as well (this may require lowering the headliner). Test the cable by itself. If the cable is shorted, replace it.
6. If the cable tests good on its own, the short is in the antenna base/amplifier assembly. Replace the antenna.
7. If the cable and antenna are not shorted, the fault may lie within the radio head unit itself. Check for any available radio software updates before replacing the unit.

Parts You'll Likely Need

• Antenna Assembly (OEM #68293977AA (Note: This is a common Mopar antenna for many models, verify fitment for the 2024+ Charger with VIN)) — If the antenna's internal amplifier fails and shorts out, it will trigger this code and cause poor reception. This is a common failure on many Stellantis products.
  Trusted brands: Mopar
  OEM price range: $100-$250
  Aftermarket price range: $70-$180
• Antenna Coaxial Cable — A pinched or damaged cable can cause a short circuit, leading to the 'Resistance Below Threshold' fault.
  Trusted brands: Mopar
  OEM price range: $50-$150
  Aftermarket price range: $40-$100

Technical Service Bulletins (TSBs) & Recalls

• 9100747: Notes that B1578 may be active without a customer complaint and advises against diagnosis in such cases.
• S258A000026: Mentions that technicians may observe DTC B1578-1A stored in the radio during a vehicle scan.

Platform-Specific Known Issues

• TSB #9100747 (dated 2025-12-15) for the 2024 Electrical System notes: 'B1578 DTC active (Audio Antenna Circuit Resistance Below Threshold) in LB production vehicles. Do not diagnose stored or active DTC unless there is a custo[mer complaint]...'
• TSB #S258A000026 (dated 2025-12-18) for the 2026 Electrical System notes: 'While Reviewing a Vehicle Scan Report the Technician May Observe That Diagnostic Trouble Code (DTC) B1578-1A Is Stored in The Radio'
• The new STLA Large platform and its associated Uconnect 5 infotainment system have been the subject of numerous software-related complaints and even class-action lawsuits, suggesting that many electronic DTCs may be spurious or software-related rather than true hardware failures.

Mechanic-Grade Diagnostic Values

• Antenna Coaxial Cable Resistance (Short Test) — expected: Greater than 47.5 Ohms. Failure: A resistance measurement below 47.5 Ohms indicates a short in the antenna cable or base.

Scan Tool Commands That Help

• Miller Special Tool #9977-6: Kit, Radio Antenna Diagnostic — This is a physical tool kit, not a software command. It contains jumpers and adapters (like 9977-6-1, 9977-6-2, 9977-6-3, 9977-6-4) that allow a technician to easily isolate and test the antenna cable and antenna base separately to pinpoint the exact location of a short or open circuit without guesswork.

Wiring & Ground Locations

• AM/FM Antenna Connector — On the back of the radio head unit.. This is the primary connection point for the antenna coaxial cable. On Chrysler/Dodge/Jeep vehicles, the AM/FM antenna typically uses a white FAKRA-style connector, which helps in correctly identifying it among other antenna connections (e.g., for satellite radio or GPS).
• Radio Coax Cable — Runs from the radio head unit, typically up a pillar and through the headliner, to the roof-mounted antenna base.. This cable is a common point of failure. A pinch or chafe along its route can cause the center conductor to short to the outer shield, triggering code B1578. The part number for the 2024 Charger Daytona is listed as 68646991AC.

Real Owner Repair Stories

• 5thGenRams Forum user 'OhioBigHorn' (2019+ Ram 1500) — No AM/FM reception, satellite radio worked fine. Code B1587 (Antenna Short to Ground) was present, which is functionally similar to B1578.
  ❌ Tried (didn't work) The dealer replaced the shark fin antenna assembly twice.
  ✅ What actually fixed it The user's final resolution was not posted, but the experience strongly indicates the fault was not the antenna itself, but rather a short in the coaxial cable running to the antenna. This highlights a common misdiagnosis where the most obvious part is replaced without testing the wiring. The user also noted a past issue with a leaking rear window, a likely cause of the wiring short.
• YouTube channel 'CarAudio.com' (Dodge Ram (generation not specified)) — AM/FM antenna had gone bad, no reception.
  ❌ Tried (didn't work) The shop verified the radio head unit was good by testing it with a known-good antenna.
  ✅ What actually fixed it Instead of replacing the factory antenna and cable, the shop installed an aftermarket powered AM/FM antenna (model 44-UA200). This antenna was mounted inside the dash, connected to the radio's antenna input, and wired to an ignition-switched power source. This completely bypassed the faulty factory antenna system and restored reception.