Repairing A Mercedes EQC 300 BEV Battery

April 22, 2026 by Maya Posch 12 Comments

When [OGS Mechanics] got a Mercedes EQC 300 battery-electric car in for repair, it was found to have a bit of a weird issue: after sitting in a garage for a while, its range on battery had suddenly reduced significantly without clear cause. Although the typical response here is to just mark the battery pack as ‘faulty’ and replace the whole unit, [OGS] decided to dig into the pack to see what was going on.

The short version is that this particular battery pack consists of two individual batteries, each with its own BMS, one of which had reported a condition to the master BMS that triggered the ‘replace battery module’ error observed with the scan tool. From this it could also be seen that the first battery was at a 10% state-of-charge (SoC), and the second at 95%, making them incredibly unbalanced. Unfortunately the dealer procedure to rebalance did not work here, with only the second battery wanting to charge even after draining both to the same initial level.

To diagnose the underlying issue in earnest required gently prying open the battery pack like a massive glued-shut smartphone. Going by the theory that it is a software glitch, since the first battery was still at a healthy voltage level, it was decided to manually charge it. With both batteries now fully charged, the BMS for the first battery was then removed to have its memory overwritten with that of a known good BMS module, clearing the ‘replace battery module’ error.

Although in the preview for the next video it’s hinted that there’s also an internal balancing issue in the first battery pack, this could be another symptom of its BMS glitching out. Either way, it would seem that BEVs battery modules are both heavily dependent on software, as well as afflicted by the same throw-away culture that has people just buying a new smartphone when the battery fails.

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CAN Bus Analyzer Runs In Your Browser

April 21, 2026 by Zoe Skyforest 11 Comments

If you’ve got a modern car, truck, or tractor, it’s probably got a CAN bus or three that is bouncing data all around the vehicle. Listening in on these transmissions can enlighten you to what’s going on with sensors and modules which can aid in troubleshooting. You might find [Chanchal]’s latest work to be helpful in this regard — a CAN bus visualizer that runs right in your browser.

CANviz, as the project is known, is designed to work with any one of a number of cheap USB CAN reader modules. To use it, you simply run the Python “pip” tool to install it, and then you have a live CAN bus frame analyzer running on your local machine. Point your browser to localhost:8080 and you can see the data pouring in from whatever you happen to be hooked up to. The tool supports decoding CAN DBC files to make better sense of the raw data coming off the bus, and you can also record sessions for later analysis and even send CAN frames yourself if you need to. You can also run the tool on a remote single-board PC if so desired and access it over a network connection from another machine.

We’ve explored CAN hacking tools before and tools for visualization as well. Often, the latter is important when trying to debug and investigate dynamic issues. Meanwhile, if you’re working on your own automotive interface hacks, don’t hesitate to notify the tipsline!

Nissan Shuts Down NissanConnect App For Older Leaf EVs

April 8, 2026 by Maya Posch 66 Comments

Back in late February Nissan Leaf owners began to receive messages from Nissan informing them that the remote features in their cars would cease operation as the NissanConnect app would drop support for Leaf EVs produced before 2020 as well as eNV200 vehicles that were produced until 2022. The indicated cut-off date was March 30, giving affected users about a month to come to terms with the fact that their vehicle would soon to losing any and all remote control features.

What this highlights is an increasingly pertinent question when it comes to ‘connected cars’, which feature a built-in wireless modem to provide a range of additional features. These require access to a remote server for even simple remote features like controlling the charging process or turning on the heating. This has left many Leaf users rather dissatisfied.

While for such basic remote features you could make the argument that they’re just silly convenience features that do not affect the car’s functionality, modern cars are increasingly becoming reliant on such remote features, including for things like navigation and checking subscriptions for features like heated seats.

Increasingly it would seem that we’re looking at the Car-as-a-Service (CaaS) model being implemented.

Setting Up Tesla Model 3’s Computer For Bug Hunting

March 28, 2026 by Maya Posch 12 Comments

Like many high-tech companies Tesla runs a bug bounty program. But in the case of a car manufacturer, this means that you either already have one of their cars, are interested in buying one, or can gain access to its software-bits in another legal manner. Being a Tesla-less individual, yet with an interest in hunting bugs [David Schütz] thus decided to pursue the option of obtaining the required parts from crashed Tesla cars.

Specifically [David] was interested in the Tesla Model 3 and its combined Media Control Unit (MCU) and Autopilot computer (AAP) assembly. In addition to the main unit, it also requires – obviously – a power supply, and the proprietary display. These were all obtained fairly easily, but unfortunately the devices all had their cables cut off, leaving just a sad little stump of wiring with the still plugged-in connectors.

After trying his luck with an incompatible BMW LVDS cable from one of their headunit infotainment systems, he then proceeded to try and use the cable stumps with some creative patching. This briefly worked, but some debris fell onto the MCU board and blew a power rail IC.

Ultimately this IC got swapped after [David] had already purchased a whole new Model 3 computer, leaving him with two units and the easy way out of buying the Dashboard Wiring Harness cable loom that contained the Rosenberger connectors he needed to connect the display to the main unit.

A Voltage Regulator Before Electronics

March 16, 2026 by Jenny List 40 Comments

Did you ever wonder how the mechanical voltage regulator — that big black box wired up to the generator on a car from the ’60s or before — worked? [Jonelsonster] has some answers.

For most people in 2026 an old car perhaps means one from the 20th century, now that vehicles from the 1990s and 2000s have become the beloved jalopies of sallow youths with a liking for older cars and a low budget. But even a 1990s vehicle is modern in terms of its technology, because a computer controls the show. It has electronic fuel injection (EFI), anti-lock braking system (ABS), closed loop emissions control, and the like.

Go back in time to the 1970s, and you’ll find minimal electronics in the average car. The ABS is gone, and the closest thing you might find to EFI is an electronic ignition where the points in the distributor have been replaced with a simple transistor. Perhaps an electronic voltage regulator on the alternator. Much earlier than that and everything was mechanical, be that the ignition, or that regulator.

The video below the break has a pair of units, it seems from 1940s tractors. They would have had a DC generator, a spinning coil with a commutator and brushes, in a magnetic field provided by another coil. These things weren’t particularly powerful by today’s standards and sometimes their charging could be a little lackluster, but they did work. We get to see how, as he lifts the lid off to reveal what look like a set of relays.

We’re shown the functions of each of the three coils with the aid of a lab power supply; we have a reverse current relay that disconnects the generator if the battery tries to power it, an over-current relay that disconnects the field coil if the current is too high, and an over-voltage relay that does the same for voltage. The regulating comes down to the magnetic characteristics, and while it’s crude, it does the job.

We remember European devices with two coils and no field terminal, but the principle is the same. There is never a dull moment when you own an all mechanical car.

Continue reading “A Voltage Regulator Before Electronics” →

Ford, Take Note: Classic Pickup Becomes The EV We Want

March 13, 2026 by Tyler August 66 Comments

Ford does sell an electric pickup, but not very many of them. We can’t say for sure, but it’s possible that if the F150 Lightning had the classic cool of [ScottenMotors] 1977 F150 SuperCab conversion they’d have better numbers.

The battery box sits where a V8 used to choke on well-meaning emissions controls.

On Reddit, [Scotten] shares the takeaways from his conversion effort, which involved a custom Tesla-cell battery pack and a new rear axle assembly to house the Tesla SDU (Small Drive Unit). A Large Drive Unit (LDU) would probably fit, but the SDU already puts out 264 HP, which compares rather favourably to the 156 HP this truck’s malaise-era V8 put out stock. The old F-bodies were great trucks in a lot of respects, but even an die-hard ICE enthusiast is probably not going to be sad to see that motor go.

Continue reading “Ford, Take Note: Classic Pickup Becomes The EV We Want” →

A circuit board card is shown, with a blue panel on one side. On the panel are switches and an RS-232 port.

Spoofing An Emergency Traffic Preemption Signal

March 8, 2026 by Aaron Beckendorf 41 Comments

There’s a well-known movie trope in which a hacker takes control of the traffic lights in a city, causing general mayhem or creating a clear getaway path. Unlike many Hollywood representations of hacking, this is actually possible in principle; many cities install Emergency Vehicle Preemption (EVP) systems in their traffic signals to turn them green when an emergency vehicle is approaching. To see what it would actually take to control one of these, [xssfox] reverse-engineered a Strobecom II EVP system.

Most EVP systems, particularly older ones, use a strobing infrared light to alert a traffic signal to an approaching emergency vehicle. To avoid misuse, vehicles often encode a vehicle ID in the infrared signal. There have been some claims that a Flipper Zero can trigger these systems, but none that were well-verified, and probably with good reason; anyone actually trying this against a live system is courting serious legal trouble. To see whether this was actually possible [xssfox] obtained real hardware and tried to reverse-engineer the infrared protocol.

There are two main manufacturers for optical EVP systems: GTT Opticom and Tomar Strobecom. [xssfox] managed to buy a Tomar power supply which handled the processing for signal transmission, and which worked with Opticom systems. Looking at the output of this revealed that it encoded data by skipping pulses, which should be simple enough for Flipper Zero to replicate.

To reverse-engineer the Strobecom protocol, [xssfox] managed to buy a Strobecom optical signal processor, which would normally detect an emergency signal. This worked by modulating the length of infrared pulses. After some brute-forcing, a transmitter using an Arduino Nano and an infrared LED managed to activate the preemption signal, and even to transmit a vehicle ID. It seems that Strobecom systems, at least, are fairly demanding in terms of the signals they accept; signals had to be precisely timed, and in at least some systems, a valid vehicle ID would be needed to change the light.

If you’d like to learn more, we’ve gone into the technology of North American traffic signals before.