ZeDefender wrote:

Why is your hand so shiny?
Love the colour (the scanner, not your hand...)

It's called the Sun Matt. We don't see it much lately though.  Diesel$ Live$ Matter. ⛽ï¸�🛢ï¸�👨â€�🔧🧰⚙ï¸� RED, WHITE & BOOST! 🇬🇧

Some info on the MIL light and DTC's from another thread.

lorryman100 wrote:

Thought I would try and explain the differences in DTC codes. So here goes:

There are basically two types of DTC codes for OBDII Diagnostics:

Emissions related DTC's Tested DTC's
Type A

1. Emissions related.
2. The Malfunction Indicator Lamp (MIL) will be illuminated as soon as the error occurs.
3. Stores a freeze frame DTC after one failed driving cycle.( history DTC is stored )

Type B

1. Emissions related.
2. Sets a Pending Trouble Code after one failed driving cycle.
3. Clears a Pending Trouble Code after one successful driving cycle.
4. Turns on the MIL after two/three consecutive failed driving cycles.
5. Stores a Pending Trouble Code as a DTC after two consecutive failed driving cycles.

Conditions for Clearing the MIL/DTC – Type A or Type B

The MIL will turn off after four consecutive driving cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using a scan/diagnostic tool.

Non–Emissions Related DTCs Un Tested DTC's

Action Taken When the DTC Sets

1. The Malfunction Indicator Lamp (MIL) will not illuminate.
2. The ECM will record a DTC at the time the diagnostic fails.

Conditions for Clearing the DTC

A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using a scan/diagnostic tool.

How to read a DTC Code

The DTC value will help you narrow down the specific component or module in question. A DTC has a standardized format that can be interpreted as follows:
The first part of the DTC is the Alpha Designator. The alpha designator will be:

B - Body electronics (i.e., door and hood latches)
C - Chassis (i.e., traction control or ABS)
P - Powertrain (i.e., engine, transmission)
U - Network communications for the different control modules

Second Digit - Code Type
The second digit identifies whether the code is a generic code (same on all OBD-II equpped vehicles), or a manufacturer specific code.

0 = Generic (The diagnostic codes that are required by law on all OBD II systems are "generic" in the sense that all vehicle manufacturers use the same common code list and the same 16-pin diagnostic connector. Thus, a P0301 misfire code on a Ford means the same thing on a Vauxhall, Citroen, Toyota or Mercedes.)

1 = Enhanced ( Each vehicle manufacturers also have the freedom to add their own "enhanced" codes to provide even more detailed information about various faults. Enhanced codes also cover non-emission related failures that occur outside the engine control system. These include ABS codes, HVAC codes, airbag codes and other body and electrical codes.)

Third Digit - Sub-System

The third digit denotes the type of sub-system that pertains to the code

1 = Emission Management (Fuel or Air)
2 = Injector Circuit (Fuel or Air)
3 = Ignition or Misfire
4 = Emission Control
5 = Vehicle Speed & Idle Control
6 = Computer & Output Circuit
7 = Transmission
8 = Transmission
9 = SAE Reserved
0 = SAE Reserved

Fourth and Fifth Digits
These digits, along with the others, are variable, and relate to a particular problem code error number

So let's diagnose a DTC, I've picked P0404-73 EGR control circuit range/performance: actuator stuck closed

so we have:
P = Powertrain (engine, transmission)
0 = Generic
4 = Emissions control
0 4 =This is the specific error code within Emission control. In this case the EGR control circuit range/performance
-73= This is a specific problem, in this case the actuator is stuck closed.