TechMade

14/07/2026

This 2022 fiesta was recently in the workshop.

Just been re-gassed by a local garage but the AC was still intermittent.

A quick scan revealed no fault codes present relating to the AC. Wiring, control, temp sensors and pressure switch all tested ok and I was able to prove the ecu was capable of commanding the compressor clutch on, but something was preventing it

This one was a classic case of modern vehicle strategies catching a technician out if they don't look at the bigger picture.

Modern smart-charging systems are programmed to shed non-essential loads to prioritize battery recovery. The ECU was intentionally disabling the AC compressor to reduce engine load and alternator demand until the battery state of charge (SoC) crossed its programmed threshold

A couple of hours on the battery charger proved the fault and customer advised of issue.

10/07/2026

End of another week and a couple of brilliant diagnostic jobs in the shop today that perfectly highlight why guessing never beats proper testing and scoping.

This Ford Ranger I found particularly interesting.

This one came in with a noticeable rough idle and a distinct injector knock. I used the oscilloscope and let the data tell the story.
Conducted a relative compression test, which confirmed even compression across all cylinders. This ruled out mechanical base-engine failure.
Hooked up the pulse sensor to analyse the crankcase first with a sinc on cylinder 1 injector

What was fascinating was capturing the actual physical sound of the injector knock. By placing the pulse sensor on the crankcase, the scope clearly captured the mechanical shockwave of the knock when induced, definitively pinning the issue to Cylinder 4.

I backed this up by checking the exhaust pulses, which showed a significantly lower contribution from Cylinder 4,

Scope waveforms don't just show voltage and current; with the right pressure/pulse transducers, you can visually map mechanical noises and gas dynamics to exact engine cycles.

26/06/2026

Certainly been a warm one, topped over 43°c in our workshop today.

Have a great weekend everyone.

23/06/2026

2 more available now

For professional use only:- Until now, the industry advice has been "Never use a test lamp on 5V sensors" because standard 12V incandescent test lamps pull too much current and can instantly destroy a delicate ECU driver channel or more likely will just short the circuit to ground. This custom-engin...

21/06/2026

I have just a limited number of these available right now.

If there’s demand I will make some more.

Hope everyone’s had a great weekend.

For professional use only:- Until now, the industry advice has been "Never use a test lamp on 5V sensors" because standard 12V incandescent test lamps pull too much current and can instantly destroy a delicate ECU driver channel or more likely will just short the circuit to ground. This custom-engin...

16/06/2026

5V Reference Test Lamp.

I’ve had a couple of enquiries recently about a dedicated test lamp for loading 5V reference circuits during automotive diagnostic work. It’s not something I’ve really considered and not sure if it had any real practical use bearing in mind that the voltage from the ECU is already dropped down.
I’ve made this one out of pure interest and will possibly put together a small prototype run if any demand.

The idea is a safe, low-draw 5v tool to verify circuit integrity under a light load without damaging sensitive ECU circuitry/channels.

These bulbs were rated/advertised 140mA, although bench testing shows they actually pull a stable 80mA instead.

As you can see in the photos, when back probing the 5V reference line, the lamp illuminates. With the test lamp loading the circuit, measuring the voltage the multimeter shows a reading of 4.969V. Although a measureable voltage drop from just over 5v, it is negligible keeping the circuit well within working specification while proving the wire can support a load.

Drop a comment below your thoughts or if you’re interested in grabbing one.

14/06/2026

Mini magnetic bus box,
1.5m silicone lead and croc clip

1 available now, will have more assembled next week

https://ebay.io/m/w6r5FU 👇

This magnetic Diagnostic bus box is a versatile tool designed for automotive testing. It comes with a 1.5m flexible test lead and clip, making it easy to diagnose faults in vehicles, With a voltage range of 24 and 12 volts max 13amps, this unit is suitable for a wide range of automotive applications...

13/06/2026

Hoping to get some of these mini-bus boxes put together when I can decide what colour to make them.

Have a great weekend everyone.

12/06/2026

A busy week in the workshop but this Focus was of particular note this week came in with an intermittent, parasitic drain. For periods would be fine then pulling a current fluctuating between 300mA and 900mA, completely flattening the battery overnight.
Initial diagnostic testing showed that the Mid-Speed CAN bus (MS-CAN) was being actively forced awake, but isolating the usual suspects the stereo, the instrument cluster, Bluetooth module and the keyless vehicle module didn't stop the sporadic cycling.

After dropping and opening up the BCM (see pictures). Severe corrosion showing this issue here, common with these vehicles.

It’s not very often I need 3 multimeters on one job (one measuring draw from the battery, one monitoring the ms can and one to volt drop test the fuses) as well as a clamp meter measure the current into the BCM.

31/05/2026

The new test lamps are now available in my shop so check them out.

There’s a few bits unavailable at the moment the extra long multicolour back probes have sold out and I’ll be making a few more in the coming days along with the junction boxes with the built in test leads.

Hope everyone’s had a great weekend