The no-sound fault in the Scania AUS4 Basic radio (Harman/Becker) is an electronic failure of the audio section on the main board. It shows up as complete silence from all sound sources (FM, DAB, USB, Bluetooth) or a whine from the speakers even when the radio is switched off.
You are halfway through a multi-day route. You are trying to concentrate on the road, but a loud, high-pitched whine is coming from your Scania’s speakers. The radio is off, yet the whine carries on. Another time there is simply dead silence.
The radio, USB and Bluetooth do not work – nothing does.
After 12 hours of driving in silence or with a whine in the background, the comfort of a long journey disappears.
This is not a one-off fault. The no-sound problem in Scania AUS4 Basic affects many units in this series. Before you start looking for a used radio (2-4 thousand zł + the risk of an anti-theft lock + another few hundred zł in an authorised dealer Scania workshop for programming) or hear the price of a new unit from an authorised dealer (~5000 zł), check our solution. Refurbishment of your original radio. Cost: 2460 zł incl. VAT. Time: 1-3 working days. Warranty: 24 months. Most importantly: works immediately after installation – no programming at authorised dealer, no hidden costs.
How do you identify the Scania AUS4 Basic radio?
The Scania AUS4 Basic radio is an audio system with a 5-inch colour touchscreen, made by Harman/Becker. It comes in two versions: HB A557 (without DAB) and HB A558 (with DAB digital radio). The simplest way to identify it is to check the label on the casing. The unit does not have navigation functions (this is what distinguishes it from the AUS4 STD model).
Label details
To make sure you have exactly this model, check the following details:
• Model: Scania AUS4 BASIC or Scania AUS4 BASIC DAB
• Part number: HB A557 (without DAB) or HB A558 (with DAB)
• Manufacturer: Harman/Becker Automotive Systems GmbH
• Label on the panel: SCANIA INFOTAINMENT SYSTEM
• Screen: 5 inches, colour, touchscreen
• Vehicles: Scania tractors (all models fitted with AUS4 Basic)
Difference between AUS4 Basic and AUS4 STD?
Important: this article covers the Basic version only (5″ screen, without navigation). If you have AUS4 STD (colour touchscreen with navigation) – that is a separate unit with a different design.
If you have an older Scania radio (AUS3 or AUS3 TIP), see our article on the Scania AUS3 model – the identification process is similar, but the construction differs significantly.
Symptoms of the sound fault in Scania AUS4
The most common symptoms are a loud whine from the speakers (even after the radio is switched off), complete silence, or erratic volume control. If you recognise any of them, your radio needs refurbishment.
1. Whine from the speakers even when the radio is switched off
This is the most irritating and distinctive symptom. A high-pitched, loud whine or squeal comes from the speakers. Crucially:
- The whine can be heard regardless of the source (FM, USB, Bluetooth).
- The whine can often still be heard even after the radio is switched off with the key or the volume is turned down to zero.
- The sound makes driving and resting in the cab impossible.
A customer from Kołobrzeg described it like this: “I could hear the whine even after taking the key out of the ignition. Only disconnecting the battery gave me silence.”
2. Complete lack of sound (from all sources)
The radio switches on normally. The 5″ screen works, you can change stations and connect via Bluetooth, but absolutely no sound comes from the speakers. There is complete silence on every source.
The problem may appear suddenly (you switch it on in the morning – silence) or gradually (first quiet crackling, then the sound disappears for a few seconds, and finally it vanishes completely). Sometimes it appears after a longer stop (for example after the weekend).
3. “Jumping” volume control
When you try to adjust the volume (even if there is silence), the volume indicator on the screen goes “haywire” – it jumps up and down by itself, even though you are turning the knob smoothly in only one direction.
You try to turn the volume up – the indicator on the screen jumps forwards and back. The control does not work properly. With one turn of the knob, the volume level randomly fluctuates between 0 and maximum.
This is not always the fault of a damaged encoder (although such faults do happen and we repair those too). Most often, the erratic jumping of the control is a symptom of the main fault in the audio section.
Why does the Scania AUS4 radio stop working? Main causes of the problem
The fault occurs in the audio section on the main board – the components responsible for processing and amplifying the signal lose their parameters after years of use. The problem gets worse gradually: first crackling when switched on, then whine, and finally complete silence.
It is not the fuse or the aerial
If the display works normally, you can rule out:
❌ Fuse – if it were blown, you would have neither picture nor any functions
❌ Aerial – the problem affects all sources (FM, DAB, USB, Bluetooth), not just the radio
❌ Speakers – it is unlikely that all speakers would burn out at once
❌ Wiring – cables do not “whine” or generate signals
There is only one option left: a hardware fault on the radio’s main board.
Why does the screen work but there is no sound?
The Scania AUS4 radio has two independent sections on the main board:
- Display section – processor, memory, screen drivers → working
- Audio section – signal processing path, amplifier → faulty
That’s why you can see: “FM 103.50 MHz”, you can switch stations and adjust settings – but there is silence from the speakers. The problem is in the audio section, not in the radio’s “brain”.
Why doesn’t the radio reset work?
Reset = software restart.
No sound = physical damage to components on the board.
It’s like trying to restart a computer with damaged RAM – it won’t help, because the problem is hardware-related, not software-related.
What people try (and why it doesn’t work):
- ❌ Disconnecting the battery for 10–15 minutes → the radio will “forget” the settings, but the damaged components will remain damaged
- ❌ Factory reset → restores the default settings, but won’t repair the main board
- ❌ Firmware update → Scania AUS4 Basic does not have a user update function, and in any case the problem is not in the software
Damage to the audio path components
The fault directly affects the components on the main board. Over time, or as a result of wear and tear, the electronic components in the audio path fail.
Repair process step by step
Refurbishment of Scania AUS4 Basic takes 1-3 working days and follows predictable stages: (1) courier dispatch, (2) diagnostics on a test bench, (3) main board refurbishment, (4) several hours of testing and return shipping. You don’t need to worry about logistics – everything is insured and you can track the parcel online.
Detailed shipping and repair process
You’ll find the full process description (how to pack it, where to send it, what the diagnostics look like, what about payment) here:
👉 Send for repair – full instructions
We won’t duplicate this information – everything is described in detail on the process page.
Refurbishment of the AUS4 Basic radio takes 1-3 working days in total. The process is simple: you send the radio, we repair it, test it and send it back “Plug & Play” – with no programming required.
How do we test the radio?
We run the radio on a test bench that simulates operating conditions in the vehicle.
Test environment:
- Power supply (as in a Scania lorry)
- Speakers connected to all channels
- FM/DAB antenna (we check actual reception)
- Full simulation: FM radio, DAB, USB, Bluetooth, AUX
What do we check:
- Whether the sound is clean (no hiss, whine or crackles)
- Whether all sources work properly
- Whether the volume control is smooth and predictable
- Whether the radio overheats during prolonged operation
After successful verification, the radio is safely packed and sent back to the customer.
We specialise in repairing factory navigation systems for lorries – see our full range of services for MAN, Scania, Volvo and other brands.
What if the radio is working?
A rare but possible scenario: sometimes the radio reaches us and works perfectly on the test bench. In that case:
- We contact you by phone
- We explain the situation (the problem may be temporary or related to the vehicle installation)
- We do not charge for the repair, and we return the radio free of charge
Why is no reprogramming needed after repair?
The key difference vs buying a used unit: after our refurbishment we do not interfere with the radio software. The radio remains paired with your vehicle (VIN number, settings). Once fitted, it works straight away – no visit to a Scania dealership, no coding, no additional costs.
Price, time and warranty – how much does the repair cost?
Refurbishment of the Scania AUS4 Basic radio costs 2460 zł incl. VAT, takes 1-3 working days and comes with a 24-month warranty.
Price details
| Item | Value |
|---|---|
| Refurbishment price | 2460 zł incl. VAT |
| Turnaround time | 1-3 working days (from receipt of the radio) |
| Warranty | 24 months (written) |
| Diagnostics | Included in the repair price |
| VIN programming | Not required (savings) |
What is included in the price:
- Full diagnostics of the unit on a test bench.
- Specialist repair (refurbishment) of the main board.
- Replacement of damaged components with new ones.
- Final testing after repair.
- Written 24-month warranty (VAT invoice).
Why is a used radio a trap?
Buying a used AUS4 radio may seem tempting, but it is only apparent savings.
- VIN lock: These radios are factory-paired with the vehicle’s body number (VIN). After fitting a “used” unit in another tractor, the radio will detect the mismatch after a few starts and lock itself, displaying an anti-theft message.
- Need for programming: The only solution is a visit to a Scania authorised dealer, paying for the diagnostic service and the costly (several hundred złoty) reprogramming of the radio to the new VIN.
- Risk of failure: A used radio has the same factory defect as your current one and may start to squeal after a few months.
FAQ – Frequently asked questions
Answers to the most common questions about Scania AUS4 Basic radio repair.
What do customers say about OEMatic repairs?
About the author of this article
This article was prepared by the OEMatic service technical team. We specialise in advanced diagnostics and repair of factory audio and navigation systems in heavy vehicles (MAN, Scania) and premium brands. We have over 10 years of experience in refurbishing Harman/Becker and Bosch electronics. We have hundreds of successfully repaired radios and navigation units with audio faults to our name.
Restore sound and peace in your Scania – book a repair
Don’t let an annoying squeal or dead silence take away the comfort of driving your Scania.
Book AUS4 Basic radio refurbishment today.
Regain full functionality of your factory audio system. The process is simple:
- Remove the radio.
- Fill in the repair order form.
- Send the unit to us.
