Extra Gauge for BMW E36, E39, E46: Oil Temp & Boost
An extra gauge for the BMW E36, E39 and E46 that reads live data from the engine ECU: coolant and oil temperature, boost, lambda. Custom alarms, DIY install.
Updated: 18 October 2026
The Elrandos extra gauge for the BMW E36, E39 and E46 shows live data straight from the engine ECU: RPM, coolant and oil temperature, boost pressure, voltage and the readings the factory cluster leaves out. You can set your own alarms for each of them.
What the extra gauge shows in the E36, E39 and E46
What you get depends on the ECU your engine has. The gauge talks to it directly, so the data is live. For anything the ECU does not report, there is an add-on sensor module (see below).
- Petrol (MS41, MS42, MS43, MS45) – RPM, coolant temperature, intake air temperature, voltage and lambda sensor signal. MS41, MS42 and MS43 also report fuel trims, and MS45 reports ignition timing, injection time and accelerator pedal position. The full list for each ECU is in the questions at the bottom.
- Oil temperature – from the MS42 and MS43 ECUs. MS41, MS45 and the diesels (DDE) do not report it, so there oil is measured with the add-on sensor module (see below). What oil temperature is normal is covered in our guide BMW Oil Temperature.
- Diesel (DDE) – RPM, coolant temperature, boost pressure, air mass, accelerator pedal position and voltage. DDE 4.0 and 5.0 also report fuel rail pressure, and DDE 5.0 adds engine torque and exhaust gas temperature before the catalytic converter.
Compatible engines and BMW models
The gauge works with these engine ECUs:
- MS41 (M52) – E36 320i, 323i, 328i; E39 520i, 523i, 528i (up to 1998)
- MS42 (M52TU) – E46 320i, 323i, 328i; E39 520i, 523i, 528i (1998–2000)
- MS43 (M54) – E46 320i, 325i, 330i; E39 520i, 525i, 530i (from 2000)
- MS45 (late M54) – in the E36, E39 and E46 after an engine swap
- DDE 3.0 (M47) – E46 320d 136 hp; E39 520d
- DDE 4.0 (M57) – E46 330d 184 hp; E39 525d, 530d
- DDE 5.0 (M47TU, M57TU) – E46 318d, 320d 150 hp, 330d 204 hp
Add-on sensor module
The gauge supports an optional module that connects to it wirelessly and reads sensors the ECU does not have. It helps where the ECU does not report something, e.g. oil temperature and pressure on the MS41 or the diesels.
- Bosch 2-in-1 sensor – temperature and pressure in one sensor.
- NTC sensors – various types.
- 0–5 V inputs – for sensors with a voltage output.
The module is still in development and is sold separately.
It talks to the ECU, not to the car
The gauge has no idea it lives in a BMW. It talks to the engine ECU and that is all it needs. If an engine from the list is doing the work, it does not care what is around it: an E46, a speedboat or a tractor. Got a test bench with one of these engines? You can fit it there too.
Done an engine swap? An E46 engine in an E36, the other way round, or no car at all? Not a problem. As long as the engine is on the list above, the gauge shows everything just like in a stock car.
In the E36, E39 and E46 the gauge goes into the instrument cluster. You can fit it in any other car, boat, tractor or test bench as well, you just position the screen yourself and tuck the circuit board away somewhere convenient.
Installation: what you need
- Torx T9 – to open the instrument cluster.
- Soldering iron – basic soldering skills help.
- Some hands-on skill – welcome.
Installation is easy and you can do it yourself. The kit comes with a PDF installation guide: step by step, with photos.
Setup: ECU, alarms, colours
After installation you set the gauge up in a web app. It only takes a few settings:
- ECU – pick the one your engine has (see the list above).
- Alarms – for every parameter you set two alarm levels with your own thresholds, e.g. a coolant temperature alarm at 120 °C or an oil temperature alarm.
- Look – the screen colours are fully customisable.
Is it safe and is it legal
The gauge does not change anything in the engine ECU. It works only in diagnostic mode and only reads parameters from the ECU, exactly like any diagnostic tool. It does not touch safety systems, does not change ECU settings and does not program anything in it.
The gauge has no certifications, though, so it is intended for motorsport and off-road use only.
Frequently asked questions
Does the gauge need to be set up?
Yes, in a web app, but it only takes a few settings: pick your engine ECU, set the alarms (two levels with your own thresholds for every parameter, e.g. at 120 °C coolant) and, if you like, the screen colours. The gauge does not change or program the engine ECU itself.
Can I install it myself?
Yes. You need a Torx T9 to open the instrument cluster and a soldering iron, so basic soldering skills and some hands-on skill help.
Which engines does the gauge work with?
Engines with the MS41, MS42, MS43, MS45, DDE 3.0, DDE 4.0 and DDE 5.0 ECUs: M52, M52TU, M54, M47, M47TU, M57 and M57TU. In practice that includes the E36 323i and 328i, E39 520i–530i, 520d and 530d, and E46 320i–330i, 320d and 330d.
Which parameters can I read from the MS41 ECU (M52)?
• engine speed (RPM) • coolant temperature • intake air temperature • engine load • idle control • throttle position • battery voltage • lambda sensor signal (bank 1 and 2) • short-term fuel trims (bank 1 and 2) • long-term fuel trims (bank 1 and 2) This ECU does not report oil temperature. The add-on sensor module covers that.
Which parameters can I read from the MS42 ECU (M52TU)?
• engine speed (RPM) • coolant temperature • radiator outlet coolant temperature • oil temperature • intake air temperature • battery voltage • lambda sensor signal (bank 1 and 2) • long-term fuel trims (bank 1 and 2)
Which parameters can I read from the MS43 ECU (M54)?
• engine speed (RPM) • coolant temperature • radiator outlet coolant temperature • oil temperature • intake air temperature • battery voltage • lambda sensor signal (bank 1 and 2) • long-term fuel trims (bank 1 and 2)
Which parameters can I read from the MS45 ECU (late M54)?
• engine speed (RPM) • coolant temperature • intake air temperature • air mass • throttle position • accelerator pedal position • ignition timing • injection time • battery voltage • lambda sensor signal (bank 1 and 2) This ECU does not report oil temperature. The add-on sensor module covers that.
Which parameters can I read from the DDE 3.0 ECU (M47)?
• engine speed (RPM) • coolant temperature • injection pump temperature • air mass • boost pressure (actual and target) • accelerator pedal position • injection quantity • injection timing (actual and target) • battery voltage This ECU does not report oil temperature. The add-on sensor module covers that.
Which parameters can I read from the DDE 4.0 ECU (M57)?
• engine speed (RPM) • coolant temperature • intake air temperature • air mass (actual and target) • boost pressure (actual and target) • fuel rail pressure (actual and target) • fuel supply pressure • accelerator pedal position • injection quantity • battery voltage This ECU does not report oil temperature. The add-on sensor module covers that.
Which parameters can I read from the DDE 5.0 ECU (M47TU and M57TU)?
• engine speed (RPM) • coolant temperature • intake air temperature • boost pressure • air mass per cylinder • engine torque (percent) • accelerator pedal position • fuel temperature • exhaust gas temperature before the catalytic converter • fuel rail pressure (actual and target) • battery voltage This ECU does not report oil temperature. The add-on sensor module covers that.
Can I change the units, e.g. °C to °F or bar to psi?
Temperatures, yes: °C or °F. Boost pressure units can be changed on diesels with DDE 5.0: hPa, mbar, kPa, bar or psi, also shown as gauge pressure relative to atmospheric pressure. DDE 3.0 and 4.0 show boost in hPa (mbar).
Will the gauge show oil temperature?
With the MS42 and MS43 ECUs, yes, straight from the ECU. MS41, MS45 and the diesels (DDE) do not report it. There, oil temperature, and oil pressure too, come from the add-on sensor module, which connects wirelessly (in development, sold separately).
Which sensors does the add-on module support?
The Bosch 2-in-1 sensor (temperature and pressure), various NTC sensors and 0–5 V inputs. The module connects to the gauge wirelessly and is still in development.
Can I use it in another car, a boat or a tractor?
Yes, if it has an engine from the list. The gauge talks to the ECU, not to the car, so it does not matter what the engine drives. Outside the E36, E39 and E46 you position the screen yourself and tuck the circuit board away somewhere convenient.
Is the gauge safe and legal?
The gauge only reads data in diagnostic mode, like any diagnostic tool, and does not touch safety systems. It has no certifications, though, so it is intended for motorsport and off-road use only.