A case where the ECU does not fail, but changes its behaviour – Siemens Sirius32 / S110030006B / 7700110471.
In the workshop, these units don’t come in with a clear history. It doesn’t start with ‘won’t start’ or ‘cuts out’. More often, it starts with something much more difficult to diagnose – ‘it works, but not as it should’.
Analogue 10-digit codes (system interpretation):
| OBD / DF code: | Analog 10-digit code: | Meaning: |
|---|---|---|
| 3104 | 0310400001 | Ignition circuit, cylinder 1/4 – open circuit/short circuit |
| DF061 | 0006100001 | Coil group 1–4 – open circuit |
| 3114 | 0311400001 | Ignition circuit for cylinders 2 and 3 – fault |
| DF062 | 0006200001 | Coil group 2–3 – electrical fault |
| 3304 | 0330400001 | Main relay – control circuit |
| DF009 | 0000900001 | Actuator control relay |
| 4016 | 0401600001 | Internal ECU error |
| DF022 | 0002200001 | Control unit – system fault |
| 4104 | 0410400001 | ECU power supply – open circuit/short circuit |
| DF271 | 0027100001 | Relay output voltage – fault |
The engine starts up. There is no dramatic failure. But even in the first few minutes, it’s clear that something isn’t quite right. The revs aren’t as steady as they should be, the response under load is slightly ‘sluggish’, and when you ease off the throttle, there’s a moment when the handling seems to waver.
And this is where the real difficulty begins.
With Sirius32, there isn’t a wide range of error codes to explain the situation. There are no ‘self-explanatory’ errors. Instead, there is behaviour. And this behaviour often leads to the wrong conclusions.
The first thing they usually do at the garage is a mechanical check – fuel, ignition, vacuum, throttle. Everything seems fine. And that is precisely what is most confusing – nothing is obviously faulty, but the car isn’t behaving normally.
Diagnostic errors, defects and manifestations:
| Code/Symptom: | Diagnostic significance: | Real manifestation: |
|---|---|---|
| 3104 / DF061 | Error in coils 1–4 | The engine is running on two cylinders or cutting out |
| 3114 / DF062 | Group 2–3 coils | Erratic ignition / no spark |
| 3304 / DF009 | Main relay | Intermittent power loss |
| 4016 / DF022 | ECU internal fault | Various random errors |
| 4104 / DF271 | Power supply ECU | Complete or partial suspension |
| Multiple errors | Combined electrical faults | Unstable engine operation |
| Intermittent start | Interrupted start-up | It only works sometimes |
This ECU operates with minimal tolerance for deviations. This means that if any input signal starts to ‘drift’, the system does not ignore it – it uses it directly. And the result is immediately apparent in the engine’s behaviour.
Most often, the problem is not constant. It occurs at specific times – when the engine is warming up, under load, or during sudden changes in speed. Then it disappears. And that is precisely what makes diagnosis difficult, because there is no consistent symptom that can be ‘pinpointed’.
In practice, this is like a car that is sometimes perfectly normal, and at other times has slightly ‘sluggish’ responses. There seems to be no logical pattern at first glance.
And here, a classic mistake is made – people start replacing components: the throttle, sensors, coils. But the problem persists. The reason is simple: the issue isn’t with what appears to be a fault, but with the way the system interprets the signals.
External influences and factors on the module:
| Factor: | Description: | Impact on the system: |
|---|---|---|
| Faulty power supply relay | Worn or sticking relay | ECU or coil failure |
| Voltage drop | Faulty battery or alternator | ECU restart, loss of control |
| Oxidised masses | Poor connection to the chassis | False electrical faults |
| A short circuit in the installation | Damaged cables connected to coils | Deactivating cylinders |
| Overheating | High temperature in the ECU area | Degradation of drivers |
| Moisture in the buckets | Corrosion and leaks | Intermittent errors |
| Surge | Voltage spikes from the alternator | Failure of internal stages |
Sirius32 does not employ aggressive defence strategies. It does not abruptly switch to emergency mode. Rather, it ‘shifts’ its operating point when something does not suit it. This makes its behaviour different, but not obviously wrong.
Electrical stability plays a huge role here. A slight drop in voltage, an unstable load or signal noise – and the result is a change in the response, not necessarily a recorded error.
Over time, this builds up. Not as a fault, but as a deviation from normal behaviour. The car starts to feel ‘heavier’, less stable and less predictable.
The most important thing to bear in mind with this module is that it will not provide a direct answer. It is not one of those systems that tells you ‘exactly what is wrong’. It merely indicates that the balance has been disrupted.
And if this balance is not assessed correctly, the repair can easily turn into a series of fruitless replacements.
Sirius32 isn’t difficult because it’s complex. It’s difficult because it doesn’t behave like a faulty system. It behaves like a system that’s still working – but in a different way now.
This combination of errors almost always indicates a problem with the power supply or the control of the relays, rather than individual defects in coils or cylinders.
The key point is that the following are affected two ignition groups (1–4 and 2–3) at the same time. This virtually rules out a mechanical fault and points to a general control issue.
In practice, it usually begins like this:
- the engine cuts out or runs on two cylinders
- Then various DF codes appear
- Finally, the ECU starts recording internal errors
The most important observation: when there is 3304 + 4104, the problem almost always lies in the power supply circuit or the relay that supplies power to the ECU and the actuators.
Very often, coils are replaced to no avail, because in reality there is no stable power supply to them.
4016 / DF022 is the final stage – the ECU can no longer maintain normal operation and begins to log internal system errors. https://einsteinpcb.com/bg_bg/
