01305 – Databus infotainment – no signal/communication (Volkswagen)

Volkswagen-specific code — factory diagnostic data

Last updated: March 31, 2026

Definition source: Volkswagen factory description · Autel MaxiSys Ultra & EV. Diagnostic guidance is based on factory-defined fault logic for this code.

01305 means the car’s infotainment network went offline, so audio, radio, navigation, or Bluetooth may stop working. You may also lose steering wheel audio buttons or a display that normally shows station and phone info. According to Volkswagen factory diagnostic data, this code indicates “Databus infotainment – no signal/communication.” On a 2013 Volkswagen Caddy, that points to a communication loss on the infotainment data bus, not a single “bad radio” by itself. Treat it as a network integrity problem first. Confirm power, ground, wiring, and bus operation before you replace any module.

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01305 Quick Answer

01305 sets when a Volkswagen module cannot communicate on the infotainment databus. Fix it by verifying module power/ground and databus wiring integrity before condemning the head unit or gateway.

What Does 01305 Mean?

Official definition: “Databus infotainment – no signal/communication.” In plain English, one control module expected infotainment network messages and did not receive them. In practice, the infotainment system may appear “dead,” reboot, or drop features that rely on other modules.

What the module checks: the module monitors message traffic and response timing on Volkswagen’s infotainment databus (platform-dependent). It also checks that other infotainment nodes appear “present” on the network. Why it matters: this DTC only identifies a suspected trouble area. Per SAE J2012-DA guidance, the DTC message does not identify the root cause. You must prove whether the issue comes from lost power/ground, an open or short in the databus pair, a corroded connector, a module that drags the bus down, or a configuration/coding mismatch.

Theory of Operation

Under normal operation, Volkswagen infotainment modules exchange serial data messages over a dedicated infotainment network. Depending on platform, this network may be a CAN bus or an optical system with a gateway interface. The gateway and infotainment head unit route requests and status messages to related modules. The radio, display, amplifier, telephone interface, and sometimes the instrument cluster share data this way.

01305 sets when expected network traffic stops, or when a module drops off the network. A power or ground loss to any infotainment node can remove messages. A shorted databus wire, damaged twisted pair, or a connector with corrosion can block communication. One failed node can also “pull down” the network and prevent all other modules from talking.

Symptoms

You will usually notice infotainment features missing first, and the scan tool results guide the next step.

• Scan tool infotainment-related modules show “no communication,” disappear from the installed module list, or drop out intermittently during an autoscan
• Radio unit does not power up, freezes, reboots, or loses presets after key cycles
• Display center screen stays black, shows a logo loop, or shows limited “safe mode” functions only
• Audio no sound output, intermittent sound, or amplifier does not wake up
• Phone Bluetooth pairing fails, phone menu disappears, or calls drop immediately
• Controls steering wheel audio buttons or head unit knobs respond slowly or not at all
• Cluster instrument cluster stops showing radio/phone information or shows “no service” style infotainment messages

Common Causes

• Infotainment bus node powered down: A blown fuse, relay issue, or sleep/wake fault prevents the infotainment module from powering up, so other modules see no communication.
• Open circuit in the infotainment CAN wiring: A broken CAN-H or CAN-L conductor stops data flow and triggers a “no signal/communication” status.
• Short between CAN-H and CAN-L: Twisted-pair damage can short the lines together, collapsing the differential signal and silencing the bus segment.
• Short to ground or short to battery on a bus line: Chafing or water intrusion can pull a CAN line low or high and block all infotainment bus messages.
• High resistance at a connector or splice: Corrosion or a loose terminal increases resistance, distorts the waveform, and causes intermittent “no communication” events.
• Poor module power or ground under load: A weak ground point or supply feed drops voltage when the module wakes, so the module resets and disappears from the network.
• Aftermarket radio or accessory integration fault: Incorrect adapters or tapped wiring can load the bus, backfeed power, or break the factory twisted pair.
• Incorrect coding, configuration, or component protection state: A module that is not configured for the vehicle can stop responding on the infotainment databus as expected.
• Internal infotainment control module failure: A failed transceiver or internal power supply can prevent bus communication, but you must prove the network and power/ground first.

Diagnosis Steps

Use a scan tool that can run a Volkswagen full vehicle network scan and read gateway installation lists. Keep a quality DVOM for voltage-drop testing under load. A CAN-compatible scope helps confirm bus integrity without guesswork. Have wiring diagrams for the infotainment databus and power distribution. Basic back-probing tools and terminal inspection picks prevent connector damage.

1. Confirm DTC 01305 and record all related faults from every module. Save freeze frame data if your tool provides it. For communication faults, focus on ignition state, vehicle speed, battery voltage, and any gateway or infotainment-related DTCs logged at the same time. Freeze frame shows when the network lost the node.
2. Run a full network scan and note whether the infotainment module appears in the control module list. Check the gateway installation list if available. If the module does not show up at all, treat this as a hard “no communication” condition and prioritize power, ground, and bus integrity.
3. Check for pending versus stored behavior. A pending communication fault may follow a single dropout. A stored/confirmed fault usually means the condition repeated on consecutive key cycles, depending on Volkswagen monitor strategy. If the code returns immediately on key-on, suspect a hard wiring or power issue.
4. Inspect fuses and power distribution for the infotainment system before probing the module. Verify the correct fuses receive power in the expected ignition positions. Check for heat damage at fuse contacts. Do not rely on visual fuse checks alone.
5. Verify infotainment module power and ground with voltage-drop testing under load. Command the module awake if the scan tool supports it, or turn the system on to load the circuits. Measure ground drop from the module ground pin to battery negative with the circuit operating. Keep ground drop under 0.1 V. Next, check power feed drop from battery positive to the module power pin under load.
6. Inspect connectors and harness routing at the infotainment module, gateway area, and known splice points. Look for water tracks, green corrosion, bent pins, or backed-out terminals. Pay close attention to any areas disturbed by radio work. Repair terminal tension issues instead of forcing the connector.
7. Check the infotainment databus physical layer. With ignition ON, measure for proper CAN bias behavior at the module connector or at an accessible junction. Do not use ignition-OFF readings as a reference. If you see a line pulled hard high or low, isolate the short by unplugging nodes on that bus segment one at a time while monitoring the line behavior.
8. Use an oscilloscope if available to confirm CAN waveform quality with ignition ON. Look for a clean differential signal, consistent amplitude, and no heavy ringing. If the waveform looks distorted, focus on high resistance, poor splices, or incorrect twisted-pair repairs. A scope lets you confirm a wiring fault without replacing modules.
9. Perform a segment isolation test if the bus stays down. Disconnect the infotainment module and re-check network health. If other modules regain normal communication, the infotainment module or its immediate wiring likely loads the bus. If the bus remains down with the module unplugged, the fault sits in the harness, a splice, or another node on the same bus segment.
10. Confirm the repair. Clear DTCs and run another full vehicle scan. Cycle the ignition and operate the infotainment system through wake/sleep events. Use a scan tool snapshot during a road test if the complaint is intermittent. Remember the difference: freeze frame captured the conditions when 01305 set, while a snapshot captures the dropout when you try to reproduce it.

Professional tip: Treat the FTB suffix seriously when you have it. For 01305, an FTB like “-004” often maps to a “No Signal” subtype per SAE J2012-DA tables. That pushes your testing toward a node that disappears from the network, not a message plausibility problem. Prove power/ground under load first, then prove the bus physical layer with ignition ON.

Possible Fixes

• Restore power supply to the infotainment node: Replace the failed fuse, repair the fuse contact, or correct the feed issue only after you confirm the loss of power under load.
• Repair ground or power connection faults: Clean and tighten ground points, repair damaged wires, and verify less than 0.1 V drop on the ground path while the circuit operates.
• Repair CAN wiring damage correctly: Fix opens or shorts, restore twisted-pair integrity, and repair splices with proper techniques to prevent reflections and repeat failures.
• Clean, repair, or replace affected terminals/connectors: Remove corrosion, correct pin fit, and address water intrusion so the module maintains stable network contact.
• Remove or correct aftermarket integration problems: Rewire incorrect adapters, remove bus taps, and restore OEM wiring routing when an accessory causes network loading.
• Correct coding/configuration issues: Recode or configure the infotainment module and gateway installation list as required after you confirm the wiring and power/ground.
• Replace the infotainment module only after verification: Replace the control unit only when it fails isolation tests and you confirm correct power, ground, and bus integrity at its connector.

Can I Still Drive With 01305?

You can usually drive a 2013 Volkswagen Caddy with DTC 01305 because it flags an infotainment databus communication loss. The engine and brakes often keep working normally. Treat the situation differently if other warning lights appear. A network fault can sometimes affect parking aid audio, hands-free calling, or the radio mute line. If the fault coincides with low system voltage, starting and charging issues can follow. Do not ignore any steering, ABS, or airbag warnings. If multiple modules drop offline together, stop and diagnose the power and network first.

How Serious Is This Code?

01305 ranges from an inconvenience to a network health warning. When only the radio or media functions fail, the impact stays comfort-related. The risk increases when the scan shows several communication DTCs across different modules. That pattern points to power supply, ignition feed, ground, or bus wiring issues. A weak battery or charging fault can trigger widespread “no signal/communication” events. In that case, the vehicle may stall, fail to restart, or lose multiple convenience functions at once. Treat repeated 01305 events as a reason to verify network integrity and vehicle voltage stability.

Common Misdiagnoses

Technicians often replace the head unit or display first because the complaint sounds like “radio dead.” That approach wastes money and misses the root cause. 01305 only reports “Databus infotainment – no signal/communication,” not a failed module. Another common error involves clearing codes and declaring success after the radio returns. Intermittent bus faults often return after vibration, heat soak, or low voltage events. Many also skip basic power and ground checks at the infotainment module connector. Corroded grounds, loose terminals, and aftermarket splices can break communication without damaging any module.

Most Likely Fix

The most common confirmed repair directions for 01305 involve restoring clean power, ground, and network continuity to the infotainment databus node. Start by load-testing the battery and verifying stable charging. Next, inspect the infotainment module connector pins for looseness, spread, or corrosion. Verify ground integrity with a voltage drop test under load. If the vehicle has aftermarket audio equipment, remove or isolate it and recheck communication. Only after you prove correct feeds and network wiring should you consider an internal infotainment module fault or required coding for a replaced unit.

Repair Costs

Network and communication fault repairs vary by root cause — wiring/connectors are often the source, but module-level repairs or replacements can be significantly more expensive.