Sick of paying out to read ECU codes on my son’s dodgy cars,any advice?

Ask Molgrips – he’s bound to be an expert on ECUs by now.

Basic e bay code readers will give you an idea of the fault or area of the fault but without something more expensive like a cracked version of autocom that you will need softwear and leads etc and a laptop to load it on, things could get very expensive very quick. And with out very regular use and hopefully without being rude unless you know what your looking at should be reading its pointless. So my best advice would be very cheap e bay scanner and if it’s code says coil pack and you try one and it cures it great but without checking the Ecu/coil/wiring/fuel/timing/compressions it really is a guess a slightly advanced one but still a guess.

it all depends. what make is that offending car?

its better to have full version of lead for your make, as they don’t lose value … and gives you proper full read out instead of gimmicky codes which not always tell you story.

for example, VCDS for Vag cars cost £240 for sunday warrior user. dealership charge £80 per pop. i havent seen second hand VCDS sell for less than £200.

Its a punto he wants to buy,the guy selling it says there is an engine light on for the o2 sensor ,if that’s true,it seems an easy fix,but I’d like to have a way to check before we buy the car.

I remember a few years ago speaking to someone at Bosch, something like 85% of returned oxygen sensors that where tested weren’t faulty, don’t forget a oxygen sensor fault is informing the Ecu there is something wrong with the cat function I.e a misfire can cause an Ecu to read a cat fault because the sensors are seen too much un burned oxygen.
Also cheap oxy sensors are notoriously bad and genuine ones can be up to £200+ for some engines

If diagnosing, look at the live data, on the punto it’s simple to do, bank 1 sensor 1, which is pre cat, you should see the value switching, it should go from lean to rich, and back again, bank 1 sensor 2 which is post cat should be a flat line if the cat is warm and doing it’s job. It’s best to check the lambda readings with 2,500 rpm of engine revs, that way the lambda is definitely being used for control (i.e. closed loop).

As for a reasonable price code reader, I have found the launch items to be very good, and in some cases my £250 item is better on japanese cars than our all singing and dancing snapon item.

It depends what you want to do.

The first few PID messages are generic and any cheap on ELM327 based device will read these codes and you can look them up online or free software will have a list built int. You can by these readers for £10 if you use your laptop.

Then there are the manufacturer specific PID codes. Best bet is either the real deal software or some Chinese knock off that is recommended by whatever community for whatever car you drive. For ebay Chinese knock off these are about £100 ish ime.

Then there is accessing things like reprogramming of various ecus when you replace one of them, reprogram for new key e.t.c This means you need security access. This start to get harder unless someone has hacked that companies ecu or you have official software from the car manufacture. If you want to know more about this google canbus 0x27 for a rabbit hole.

Ok. So had to do this on the alfa this week.
A £7 obd lead off ebay and multiecuscan (its free!) Cured a dpf prob and diagnosed a loose sensor connection.

To say am super chuffed to fix it for £7 is an under statment.