FAQ
TL;DR: In A6 C5, many Android 2‑DIN boot loops are power faults: 12 V constant/12 V ACC plus ground. “the ground cable (-) had to be straight from the battery”. Fix by wiring A4=+12V, A7=ACC, A8=GND and using battery negative. [Elektroda, Robert180388, post #19419770]
Why it matters: It helps Audi A6 C5 owners installing Android 2‑DIN units fix boot-looping/shutdown without unnecessary returns or firmware hunts.
Quick Facts
- ISO A4 = +12 V constant, A7 = ACC +12 V after ignition, A8 = ground; confirm with your harness. [Elektroda, _carlos-, post #17812037]
- A direct battery negative resolved repeated on/off cycling for ES-series units in A6 C5 installs. [Elektroda, Robert180388, post #19419770]
- Without a CAN adapter, steering-wheel buttons fail and power on/off may rely on CAN signaling. [Elektroda, _carlos-, post #19419965]
- For diagnosis, briefly bridge ISO pins 4 and 7 with ignition on; if it stabilizes, ACC feed is suspect. [Elektroda, Darek A., #17216303]
- Erisin ES7826s (PX5, 1024x600, Android 8.0.0, MCU MTCE_LM_V2.88_1) was reported in this case. [Elektroda, Robert180388, post #17879200]
Why does my Android 2‑DIN radio boot then shut off in an Audi A6 C5?
Power instability from poor grounding causes boot loops. One A6 C5 owner fixed it by running the radio ground straight to the battery negative. Chassis or harness ground can drop voltage under load. Rewire the ground to battery, then retest boot stability. Use the factory harness for positive feeds, but isolate the ground. This simple change ended repeated on/off cycling for ES-series units. [Elektroda, Robert180388, post #19419770]
Which ISO pins supply power and ground on these head units?
ISO A-block power pins are: - A4: +12 V constant, - A7: ACC +12 V after ignition, - A8: ground. Wire them exactly as above. Verify with a multimeter before powering. If A4 and A7 are swapped in your loom, correct them. Miswiring can cause reboots or no memory retention. [Elektroda, _carlos-, post #17812037]
Can I bridge pins 4 and 7 to test if ACC is the problem?
Yes. Temporarily bridging A4 (BATT) and A7 (ACC) can confirm an ACC feed issue. Do this only for a quick test. If the radio stops rebooting, your ACC line is unstable. Then fix the ACC source or use a CAN adapter that provides ACC. How-To:
- Turn ignition ON and power the radio.
- Briefly short A4 to A7 at the ISO power block.
- If stable, rewire ACC to a clean switched 12 V. [Elektroda, Darek A., #17216303]
Do I need a CAN module in the A6 C5 for an Android radio?
If your car uses CAN for radio control, a CAN adapter is recommended. Without it, steering-wheel buttons will not work. The head unit on/off can also be signaled over CAN. Many aftermarket looms include a small CAN box. Add one that matches your vehicle type. This helps deliver a stable ACC signal and proper shutdown. [Elektroda, _carlos-, post #19419965]
My A6 C5 is pre‑2002; does it use CAN for the radio?
A6 C5 models before 2002 do not use CAN for the radio. They use analog signals instead. In that case, a CAN adapter will not help power control. Wire ACC and BATT directly via the ISO harness. This is an important edge case when choosing adapters. [Elektroda, SZYMON BYDGOSZCZ, #19420426]
I ran new power from the battery but it still reboots—what next?
Running a new positive feed may not cure reboots. One installer pulled power from the battery and the unit still cycled after minutes. Check the ground path and add a CAN module if your car uses CAN. Firmware alone may not fix a wiring fault. Focus on stable power and ground before software. [Elektroda, Robert180388, post #17815858]
How do I ground the unit to stop power cycling?
Fix the ground path. As one owner reported, “the ground cable (-) had to be straight from the battery.” How-To:
- Run a dedicated ground wire from the radio GND to the battery negative.
- Isolate or bypass the factory harness ground.
- Power on and verify the radio no longer cycles. [Elektroda, Robert180388, post #19419770]
Will a firmware update fix the on/off loop?
Not always. An Erisin ES7826s updated with “lm2_PX5_8.0_ota (20190105)” still powered on and off repeatedly. This shows software alone may not solve a power fault. Stabilize wiring first. Update firmware after power is clean and the unit boots consistently. Ask the vendor for full packages only when needed. [Elektroda, Robert180388, post #17879017]
Where do I get the correct OS and MCU files for an Erisin PX5 unit?
Request them from your seller. You need a complete operating system image and a PhoenixCard file to rewrite storage. Ask for the matching MCU package as well. Then follow the vendor’s flashing procedure. This path helped others when OTA updates failed. It ensures OS and MCU firmware are in sync. [Elektroda, _carlos-, post #17879346]
What info should I share when requesting firmware?
Provide three items so the seller can match files: - radio model, - Android version, - MCU version. Sharing precise versions speeds support and avoids wrong images. Include screenshots of the About page if possible. Sellers often ask for this data before sending files. [Elektroda, _carlos-, post #17817106]
What Android and MCU versions were reported for the ES7826s?
Erisin ES7826s details shared in the thread: - Model: PX5 (1024×600), - Android: 8.0.0, - MCU: MTCE_LM_V2.88_1 dated Jun 12, 2018. This example helps match compatible updates and MCU builds. Report exact strings when seeking firmware. These identifiers distinguish hardware variants. [Elektroda, Robert180388, post #17879200]
Does this issue affect other Erisin models?
Yes. Another owner of an Erisin ES5115V reported the same power‑cycling behavior. The symptoms and MCU family were similar. Grounding and ACC wiring checks apply across ES-series units. Use the same diagnostics before pursuing firmware changes. [Elektroda, Pojwola, post #18919367]
My unit only restarts after pressing RESET—what does that indicate?
That behavior shows the unit has power but crashes or shuts down soon after boot. The OP could restart only via the reset button. Treat this as a power stability problem first. Inspect ACC, BATT, and ground connections. Then test with a direct battery ground. [Elektroda, KrzysztofA6C5, post #17216187]
How can I bench‑test the radio outside the car to isolate wiring?
Power it directly from a 12 V battery on the bench. One installer found the radio worked perfectly when powered at home. This isolated the in‑car ground as the fault. Keep polarity correct and fuse the positive lead. If stable on the bench, rework vehicle power and ground. [Elektroda, Robert180388, post #18920382]
