CarPlay or Android Auto only charges: charge-only USB port, wrong port variant, wiring or hub
Applies to: MIB2 MST2 (VW, Skoda, SEAT units including Golf 7, Passat B8, Polo, T6); MIB2 MHS2 and MHI2 / MHI2Q (Audi A3 8V, A4 B9, A5, Q7 and similar); MIB2.5; MH2P / MS2P (Audi A1, Q3 F3 and similar); Cars where CarPlay or App Connect was retrofitted or activated after delivery
A common complaint on VW Group MIB head units is that a phone plugged into the USB socket charges but nothing else happens. CarPlay or Android Auto does not launch, the iPhone may report the device as not supported, or Android Auto works while CarPlay does not. In nearly every reported case the cause is hardware in the USB path (a charge-only socket, a port variant without Apple support, the wrong hub or missing data wiring) or the USB coding in the 5F module, rather than the head unit itself. This article covers how to tell which applies and the order in which owners worked through it.
How to recognise the problem
The phone charges on the cable, but no projection starts. Owners describe several variations of the same fault, and the exact symptom helps narrow down the cause.
- The USB socket, or the head unit's USB menu, is labelled or reported as charge-only.
- Android Auto works but CarPlay does not, or the iPhone shows 'device not supported'.
- The smartphone interface or App Connect menu appears after activation, but tapping it only opens the connection manager.
- The USB port only reads memory sticks, or reports iPod-compatible only.
- On MHI2Q units, CarPlay or Android Auto connects and drops after about one second.
- On cars with two sockets, CarPlay works on one socket and not the other.
Likely causes
Owners trace the fault to one or more of the following. Activating CarPlay in software, whether by patch, FEC or SWaP code, does not change the USB hardware. A charge-only or Android-only port stays that way after activation.
On VW-group ports the colour of the connector on the back of the socket is widely used as a guide. Purple or pink sockets are reported as Android Auto only. Green sockets are reported as CarPlay and Android Auto capable. CarPlay needs a port or hub with the Apple authentication (MFi) chip, while Android Auto works over a plain data USB connection. For this reason Android Auto often works on a port where CarPlay never will.
- Charge-only socket: common in Audi armrests and in EU cars ordered without smartphone interface. Often the socket and its wiring carry no data lines at all.
- Wrong port variant: the socket carries data but lacks Apple support. VW owners refer to the variant with a part number ending in E (for example 5G0035222E) as the CarPlay-capable one. One note also lists 5G0 035 222 H as supporting both Apple and Android.
- Hub issues: some cars route the sockets through a USB hub that will not pass CarPlay. On a Passat B8, plugging a new cable into the hub instead of directly into the CarPlay port disabled the hub.
- Wrong module for the platform: several owners report that a USB port that works on MHI2 (Nvidia) does not work on MHI2Q (Qualcomm). A VW-style port fitted to an Audi MHI2Q or MH2P unit can charge only, or connect and drop.
- Coding: the 5F long coding byte 19 does not match the fitted port. Examples are full USB instead of USB+iPod, or a leftover charge-only setting.
- Non-genuine ports: cheap clone sockets are repeatedly suspected when correct coding and activation still give no CarPlay.
- Phone in the wrong socket: on two-socket cars only one socket, usually the green or phone-icon one, carries data.
Before you start
Some fixes involve coding changes, patches or firmware updates. Before making any change, note the current firmware train and the head unit part number, and back up coding and adaptations. Keep a stable power supply connected during any update or patch. Use firmware intended for your exact unit.
Step-by-step fix
Work from the cheapest checks to the hardware changes.
- Try the other socket and another cable. On two-socket cars, move the phone to the green-connector or phone-icon socket. Ports marked charge-only do not support CarPlay. Rule out a charge-only cable as well.
- Confirm the software side is done. Check that the smartphone interface is activated. One note names FEC 00060800 for CarPlay. On some units owners also set Google_GAL, Apple_DIO, Mirror_link and Smartphone_interface_for_rhmi to ON in the 5F adaptations. Some MH2P owners used wireless CarPlay activation without changing the port.
- Check 5F long coding byte 19. For iPhone it should be set to usb_ipod or ipod_full (one note gives the value C0), not full or charge-only. One owner only got it to stick by setting byte 19 to off, saving, then setting usb_ipod. Reboot the unit after coding. Byte 19 bit 7 is the bit owners refer to for the iPod setting.
- Pull the socket and identify it. Check the connector colour and read the part number. A purple or pink connector, an iPod-only port or a charge-only socket needs replacing for CarPlay. Some units show the USB part number in the green menu. If none is shown, suspect a clone.
- Replace the port with the correct variant for your car and platform. For VW MST2/MIB2 cars, owners used the green E-suffix port (for example 5G0035222E, or a 726E-suffix port). In those cars often only the plug is swapped and the harness stays the same, though a tab on the cable plug may need trimming. For Audi MHS2/MHI2/MHI2Q, owners used the original Audi dual-USB module 8W0035736 with its wiring (a 4M0035736 variant was also mentioned). On MHI2Q, use original Audi parts with matching wiring rather than VW or aftermarket ports. For A3 8V, one owner used 8V0035708. Another reported that a single port (81A 035 736) is enough and a dual port is not required.
- Add or correct the wiring where the old socket was charge-only. Charge-only Audi sockets usually need a new harness carrying the data lines to the MIB unit, not just the charge feed. Some CarPlay ports and adapters have two extra pins that need a 5V and ground feed the old harness lacks. For MIB2, one owner used pin 3 of the green connector for 5V and pin 4 for ground. On MHI2Q, check that 5V and 12V are on the correct pins.
- Check the hub. If the car uses a hub, either connect the head unit cable directly to the CarPlay-capable port or fit a CarPlay-compatible hub with the correct pinout. One owner reported the EU hub 5Q0035953D worked where a China-sourced equivalent did not. With the A3 8V hub 81A 035 726, the green socket is for an extension to a second port. Leave it unplugged and use the brown one.
- Re-check coding after the swap. Reports differ here. Several owners needed byte 19 set to usb_ipod after fitting the new port. Others, including some Passat and Audi 8W0035736 installs, needed no coding change. On one MS2P unit, setting USB to full was enough. Check the 5F fault memory if it still fails.
- If wired data is impractical, use a wireless dongle. Several owners hid the existing socket behind the glovebox or in the armrest and plugged a wireless CarPlay or Android Auto adapter into it. Results depend on the port: CarPlay dongles are reported to need an MFi-capable port, while Android Auto dongles work on a standard data USB. Some owners reported a dongle on a charge-only port was not enough.
Firmware and platform notes
Firmware updates alone do not fix a charge-only or Android-only port. Some owners updated before patching because their train was too old for the patch, for example moving an MHI2 unit to MHI2Q_ER_AUG22_P5092. Others reported no update was needed: an A3 8V on MHI2_ER_AU37x_P4203_MU1168 was patched on its existing firmware and given a new port. On some VW T6 units the existing firmware was reported to lack the Apple/iPod mode until updated.
Head unit hardware also matters. Owners noted that some basic units cannot run App Connect regardless of the USB port. Check that your unit supports smartphone integration before buying parts.
What did not help
Owners reported the following did not work or made no difference:
- Fitting a USB-C socket from an A4 B9.5 into a B9 USB+AUX setup: it only charged.
- USB-C sockets on MHI2 in general, and double USB-C adapters on the armrest.
- Cheap AliExpress clone ports, even with the FEC active and USB mode coded correctly.
- VW ports (including 5Q0035726E) on MHI2Q, and the VW USB port on an Audi MH2P A1: these charged only or dropped the connection. Owners disagree on whether 5Q0035726E works on Audi MHI2 at all.
- A 6-pin USB port from an Audi TT (8S0035736) on an MHI2Q unit. The 8-pin version was needed.
- Activation, patching or firmware updates on their own, without fixing the port.
- Changing coding when the fitted port was the wrong hardware variant.
Frequently asked questions
- Do I need to change the USB port for Android Auto?
- Often not. Android Auto runs over a normal data USB connection, so purple or pink Android-only ports usually work for it. A fully charge-only socket with no data lines still has to be replaced or rewired.
- Why does Android Auto work but CarPlay does not?
- CarPlay needs a port or hub with the Apple authentication chip. A port without it, typically purple or pink, or a non-E-suffix VW part, gives Android Auto only. Coding byte 19 set to full instead of usb_ipod can cause the same symptom.
- Can CarPlay work on a charge-only socket without replacing it?
- On some MH2P and MIB2 units owners activated wireless CarPlay without changing the port. Wired CarPlay and Android Auto need a data-capable port. Results with wireless dongles plugged into charge-only sockets are mixed.
- Do I have to recode after swapping the port?
- It depends on the car. Several owners had to set 5F byte 19 to usb_ipod and reboot. Others reported no coding was needed after fitting the correct port.
- Why does a port that works on MHI2 fail on my MHI2Q?
- Owners report the USB modules differ between Nvidia MHI2 and Qualcomm MHI2Q. The original Audi module such as 8W0035736 with its own wiring is the commonly reported fix.