After installing a wireless Qi Charger in my 2019 SEAT Leon Sportstourer FR came the desire to also project the CarPlay screen of my iPhone X (running iOS 14.6) wirelessly. So I thought I’d give one of those adapters a shot despite the many sobering reviews. I would like to share my experience with a Carlinkit 2.0 Wireless CarPlay Adapter (CPC200-U2W Plus), the AUTOKIT one with the red UI (sometimes being referred to as 3.0), running the latest OTA firmware VER:2021.03.06.1355. My head unit is a Volkswagen MIB2 with BeatsAudioTM sound system.
The Carlinkit 2.0 adapter is a small Linux-based embedded system using a NXP/Freescale i.MX6 UltraLite SoC. Power consumption is around 1W (certainly not as low as the advertised 0.25W), leaving some power for the “passthrough” USB port, preventing a plugged-in iPhone from discharging while navigating and listening to music. It is however not enough for charging at a reasonable speed. In fact, the iPhone may even discharge when leaving the display on. I therefore strongly advise installing a dedicated car or wireless Qi charger with shorted data lines, providing >2A instead of falling back to 500mA. While on battery, wireless CarPlay drains my two-year-old iPhone X by ~15% per hour.
Many other wireless CarPlay adapters on the market (like CPLAY2air, re-STREAM) are based on the very same hard- and software. So do not expect a different outcome with those. Even the V2 of the adapter isn’t much different from V1, except for the active antenna design for improved Wi-Fi signalling and a prettier housing.
There is however also another breed of wireless CarPlay adapters (JoyeAuto/MMB) which are more like complete set-top boxes, running a full-blown Android OS, for example allowing one to watch video on the dashboard. I am not really sold on the idea, violating safe-driving principles. Plus the more potent processor will sip quite a bit more power while at the same time not helping with wireless CarPlay performance. I wonder whether every car can handle the high power draw via USB. There is certainly nothing left for charging a connected phone.
The adapter spans a Wi-Fi network on the 40MHz wide channel 38 (36+40) which the iPhone connects to. It supports Wi-Fi 4 (802.11n) 2⨯2 MIMO, resulting in a maximum link speed of 300mbps.
So this is certainly not the advertised 5.8GHz (UNII-3) band which isn’t much of a problem though. Apple isn’t specific on which band to use. They do however recommend Wi-Fi 5 (802.11ac) on 80MHz wide channels (VHT80), resulting in a maximum link speed of 867mbps. They also mandate the WMM Quality of Service mechanism for improved VoIP latency and screen reaction times. The Carlinkit 2.0 adapter’s access point offers neither despite the built-in Realtek Wi-Fi chipset (RTL8822BS) supporting both. Some outdated Realtek driver may limit the hardware’s capabilities.
Even though CarPlay is a peer-to-peer connection, probably not suffering from lots of interference while on the road, also not using a hell of a lot of bandwidth (around 10-11mbps for wireless CarPlay), I am quite confident that Wi-Fi 5 (802.11ac) / WMM may help to bring down latencies quite a bit which would be a very welcome enhancement.
Plug & Play
Installation is fairly simple. It is no harder than plugging the adapter into the USB port of a CarPlay enabled head unit and pairing the iPhone to it via Bluetooth. Wi-Fi credentials are exchanged transparently over which future connections are magically established whenever the paired iPhone gets close to the running car.
Volkswagen’s modular infotainment system (MIB) is built into many cars from their different brands (VW, AUDI, Skoda, SEAT, Porsche). So it may have received some special treatment by Carlinkit. Connecting to it is very quick and reliable. It typically takes no longer than 20 seconds after turning the ignition switch until music from the iPhone starts playing over the car’s speaker system. That’s probably not the norm though. So depending on your car, it may take a bit longer to connect.
As already pointed out, the main purpose of the Carlinkit 2.0 is to project the CarPlay screen wirelessly onto the car’s dashboard. For this to work, the car has to already support wired CarPlay via USB as the adapter “only” translates between wired and wireless worlds.
The adapter also features a second USB port for limited charging and wired CarPlay passthrough. The latter however only works by plugging the iPhone in before turning the car’s ignition switch. As soon as the Carlinkit 2.0 adapter has established a wireless connection to the iPhone, plugging the iPhone into the USB passthrough port won’t result in a switch from wireless to wired CarPlay which is perfectly within Apple’s specification though. The wireless CarPlay session however gets disconnected for a few seconds which contradicts Apple’s idea of an interruption-free operation. I would love to see a Hand-off option that allows the current wireless CarPlay session to be terminated when hot-plugging the iPhone via USB and instead establishing a wired connection, accepting the short interrupt. Either that or an interruption-free Charge only mode.
Human Machine Interface
Navigating the CarPlay interface via touchscreen is quite smooth and not perceived as being too laggy. There is not much of a difference compared to wired CarPlay. This clearly indicates that the concept indeed works.
The iPhone properly detects through the adapter that CarPlay is controlled via touchscreen rather than a selection knob or trackpad. So the iPhone does not erroneously focus on some item. Dark and light modes are switched automatically based on whether the car’s lights are on or off. So all information between head unit and phone seems to properly pass through the adapter.
Steering wheel controls for volume, track skipping (previous/next) and engaging the Siri voice assistant also work fine with hardly any lagging. Unfortunately, seeking (fast-forwarding/rewinding) the currently playing audio track by long-pressing the skip (previous/next) buttons does not work.
This is where things get more interesting. While Apple specifies uncompressed LPCM audio for wired CarPlay, wireless CarPlay uses the compressed and lossy AAC-LC format for media audio which the adapter therefore has to decode. There is no audible quality degradation which may however depend on the music service and used audio codec/bitrate combination.
For services using AAC (e.g. Apple Music), wired vs. wireless CarPlay shouldn’t make any difference. It typically doesn’t matter whether the iPhone or the adapter decodes the audio. The sound output is pretty neutral which can be optimized via equalizer of the in-car amplifier.
Spotify uses a pretty transparent 320kbps Vorbis in its highest quality preset. Transcoding that to 256kbps AAC-LC shouldn’t do too much harm with the upside of being able to use the in-app equalizer. Low bitrate MP3 internet radio stations will probably suffer the most. Those however suffer anyway, still being better than AM/FM though. Also transitioning between and mixing two audio sources works flawlessly, for example engaging Siri or the navigation app giving directions while listening to music, either via CarPlay app (e.g. Apple Music or Spotify) or the head unit.
The adapter properly handles the different types of audio (music, speech/Siri, phone call, ringtone), enabling the head unit to store separate volume levels for all of them. So you can for example turn up your music while still getting directions at a reasonable volume.
The mentioned translation between the two worlds has some negative side-effects though. There is a noticeable audio lag which can to some degree be mitigated via the Media Delay setting in the adapter’s web interface which can be reached via a web browser (URL=http://192.168.50.2) on the iPhone while being connected via wireless CarPlay.
I get reliable audio at about 500ms and above. This results in an effective delay of almost 2s which is quite a lot, given the fact that wired CarPlay is pretty instantaneous (setting Media Delay to its maximum of 2000ms results in an effective delay of >3s). It is certainly way above Apple’s requirements.
So how does this audio lag manifest itself? When for example skipping through songs, it takes the mentioned amount of time until the audio reflects the change. Also, the displayed album artwork is out of sync accordingly.
What probably has to be added is that turn-by-turn instructions arrive perfectly in time.
I don’t really know what the Sound Quality setting is really all about. It however does not seem to have an impact on audio lagging and reliability in combination with the MIB2. CarPlay only supports 16-bit audio at 44.1 and 48kHz audio. Maybe only the first is advertised in case CD is selected.
Making phone calls works in principle. There is some talking over each other every now and then which however also happens with wired CarPlay from time to time.
In order to be able to classify the phone call performance via Carlinkit 2.0 adapter and to get a better feeling about the different scenarios, I called an echo test number and measured the round-trip time (RTT or two-way-delay). With no CarPlay involved at all, RTT measured in at ~400ms, wired CarPlay gave me ~700ms and wireless CarPlay ~1000ms. That’s quite a lot. Certainly above the ITU’s proclaimed acceptable one-way delay of up to 400ms for conversational audio (recommendation is below 150ms). It is probably more of a systemic than an adapter specific problem though. There is again a format conversion involved as wireless CarPlay uses the compressed AAC-ELD format for speech.
A common problem with (wireless) CarPlay is that the iPhone may be positioned in a location without any GPS satellite visibility, e.g. in the pocket, a bag or a dedicated wireless charging cradle. In case of wireless CarPlay, Apple therefore mandates that location information of an in-car GPS antenna gets passed on to the iPhone via CarPlay enabled head unit. The MIB2 of my Leon Sportstourer comes with support for navigation, therefore featuring a GPS antenna.
Despite only supporting wired CarPlay, location information of the in-car GPS antenna is passed on to the iPhone. It also travels through the Carlinkit 2.0 adapter perfectly fine. I successfully navigated with the iPhone in my pocket using Google Maps and Sygic GPS Navigation.
Security & Support
The security of the adapter is subpar. The spanned Wi-Fi network supports WPA/WPA2 mixed mode even though every CarPlay-enabled iPhone is perfectly capable of WPA2(CCMP). What’s even more concerning is that I could manually connect to the adapter’s Wi-Fi network with another (non-paired) iPhone via the well known 12345678 passphrase and change settings or initiate a firmware update via the web interface. The adapter should in my opinion generate a random passphrase for wireless CarPlay in order to prevent manual connections which is a non-requirement anyway since the adapter isn’t supposed to act as an internet hotspot. The iPhone’s Personal Hotspot can still be used to share its cellular data connection while being connected through wireless CarPlay. The idea probably is to still have access to the adapter in case the wireless CarPlay connection fails in order to change settings or update the firmware.
Carlinkit sometimes issues multiple firmware updates in one single month, constantly fixing bugs, improving compatibility and performance. While one has to give them credit for that, quality assurance leaves to be desired with certain updates even having bricked the adapters of quite some people. In some (but not all) cases, the adapter can be recovered by flashing a rollback firmware via USB. Such rescue attempts are typically advised by online communities rather than Carlinkit‘s technical support which is a bit unfortunate. There is certainly room for improvement.
The OTA update mechanism is quite straightforward. Just visit the adapter’s web interface while being connected through wireless CarPlay. If an update is available you will be prompted to install it. The firmware image files are rather small (typically <10MB) and will be downloaded via your phone’s mobile plan.
Make sure the car engine is running while updating the firmware in order to prevent the USB from entering some power-saving state. Also do not plug the iPhone into the adapter’s USB port in order to prevent any potential disruption, either from the power or data side.
The Carlinkit 2.0 adapter does not seem to be an Apple-certified accessory. A Made for iPhone logo is nowhere to be found. With that in mind, the product isn’t exactly inexpensive either unless you get some special deal.
It looks like the adapter has come a long way and matured quite a bit over time. CarPlay however frequently freezes on me (audio cutting out and the screen not updating anymore) when the iPhone is plugged into the adapter’s USB passthrough port for charging. Only replugging the adapter takes care of the problem. This together with the low power budget limits the USB passthrough port’s usefulness. I, therefore, advise against using it. Apart from that, the Carlinkit 2.0 adapter is a decent product that probably wouldn’t pass Apple’s strict quality control though. Some quirks will hopefully be addressed via future firmware updates. There is certainly room for improvement with respect to audio lagging and stability.
Fast and reliable connection (VW MIB2)
In-car GPS passthrough
Steering wheel controls working
Easy OTA updating for continuous improvements
Respects safe-driving principles
Noticeable audio lag
Seeking music by long-pressing steering wheel’s skip buttons not working
Several USB passthrough port shortcomings (low power, crashing) limit its usefulness
Full hardware potential not leveraged
(Wi-Fi 5 / WMM / WMM Power Save)
Open gates to intruders
★★★★☆ Build Quality
Thanks: Guest written by Daniel Bechter