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Any MOT testers out there?
ChrisW - 11/1/18 at 09:24 PM

Can anyone tell me what the codes mean at the end of the failure/advisory reasons given on MOT's?

For example:

Exhaust emissions carbon monoxide content at idle excessive (7.3.D.4)

Is it possible to look up code '7.3.D.4'? Is there a list of all possible codes available somewhere?

Thanks, Chris

NigeEss - 11/1/18 at 09:52 PM

Refers to the sections of the MOT Testers Manual


7.3.D.4 is on page 12

joneh - 11/1/18 at 09:52 PM

Not an MOT tester but looking in the manual i believe the 7.3 is Section 7.3 of the manual. The D is the method of inspection, and the 4 is rejection reason.

See page 12 of section 7.3.

Edit. Pfft too slow.

[Edited on 11/1/18 by joneh]

craigdiver - 11/1/18 at 09:53 PM

MOT Fail Sheet

Listed on your MOT fail sheet is a code as to why your vehicle has failed its MOT test check. The code listed applies to the section of the MOT test that the vehicle failed. For example, code 6.1.b.2 can be broken down to the following; Section 6. Sub-Section 1. b Subject. 2 Reason for fail.

Below are the sections, sub-sections and subject items checked throughout the MOT test check that generates MOT failure codes:

Section 1: Lamps, Reflectors and Electrical Equipment

1.1 Front and Rear Position Lamps and Registration Plate Lamps

a. Front and rear position lamps
b. End outline marker lamps
c. Registration plate lamps

1.2 Stop Lamps

1.3 Rear Fog Lamps

1.4 Direction Indicators and Hazard Warning Lamps

Flashing type
Hazard warning device
Semaphore type
1.5 Rear Reflectors

1.6 Audible Warning (Horn)

1.7 Headlamps

1.8 Headlamp Aim

All headlamps
European ‘E’ Beam Headlamps
British American Type (Main Beam)
British American Type (Dipped Beam)
1.9 Electrical Wiring and Battery

Section 2: Steering and Suspension

2.1 Steering control

2.2 Steering System

2.3 Power Steering

2.4 Suspension – General

All suspension types
Leaf springs
Coil springs
Fluid/gas/air suspension
Torsion bars
Bonded suspension units
Suspension arms and linkages, sub frames etc
2.5 Front Suspension Front Wheel Bearings and Drive Shafts

Suspension joints and wheel bearings (wheels jacked)
Suspension joints (wheel on turning plates)
Front wheel drive shafts and couplings
2.6 Rear Suspension and Wheel Bearings

2.7 Shock Absorbers

2.8 Suspension Type Diagrams

Section 3: Brakes

3.1 Parking Brake Control

3.2 Hand Operated Brake Control Valves

3.3 Service Brake Control

All types of braking systems
Hydraulic systems (including servo assisted)
Vehicles with High Servo Boost
Full power hydraulic braking systems
Air and vacuum systems
3.4 Anti-lock Braking and Electronic Stability Control Systems

3.5 Mechanical Brake Components

3.6 Braking systems and Additional Braking Devices

All braking systems
Brake pipes and flexible hoses
Servos and master cylinders
Reservoirs (air/vacuum), including accumulators, pressure and vacuum vessels
Pumps and compressors
Hydraulic systems
Air systems
Additional braking devices
Electronic braking systems (class 5 only)
3.7 Brake Performance

Roller brake test
Decelerometer test
Plate brake test
Gradient test
3.8 Method of Calculating brake performance

3.9 Example of a Manufacturers Plate

Manufacturers Plate View

3.10 Brake Efficiency Tables

Section 4: Tyres and Road Wheels

4.1 Tyres

Type of structure
Load index and speed rating (applicable to class 5 and only)
Speed rating – Restricted speed vehicles (applicable to class 5 only)
Condition of tyres
Tread – pattern, breadth and depth
4.2 Road Wheels

Applicable to all vehicles
Additional checks (applicable to class 5, 7 and large class 4 only)
Section 5: Seat Belts and Supplementary Restraint Systems (SRS)

5.1 Seat Belt Requirements

General Information
Three-Wheeled Vehicles
Passenger Vehicles, Motor Caravans and Ambulances with up to 8 Passenger Seats
Minibuses, Motor Caravans and Ambulances with 9-12 Passenger Seats
Minibuses, Motor Caravans and Ambulances with 13-16 Passenger Seats
Coaches and Other Buses
Goods Vehicles and Living Vans
Seat Belt Types
5.2 Seat Belt Condition

5.3 Seat Belt Installation Requirements (Class 4A & 5A approved VTS only)

Seat belt Installation Check
Vehicles Exempt from Seat belt Installation Checks Seat belt Installation
Guidance Notes
5.4 Supplementary Restraint Systems

Section 6: Body, Structure and General Items

6.1 Vehicle Structure, Body and General Items

Vehicle structure
Body security (vehicles with separate bodies only)
Body condition
Engine mountings
Steps and stairs (class 5 only)
6.2 Seats and Doors

Passenger entrance and exit doors (class 5 only)
Emergency exits (class 5 only)
6.3 Registration Plates and Vehicle Identification Number

Registration plates
Vehicle Identification Number
Registration Plates – Additional Information
6.4 Load Security, Spare Wheel and Carrier

6.5 Speed Limiter

Speed limiter plate
Speed limiter
6.6 Towbars

6.7 Speedometer

6.8 Driving controls (Class 5 only)

6.9 Glazing (Class 5 only)

Section 7: Exhaust, fuel and Emissions

7.1 Exhaust system

7.2 Fuel System

7.3 Exhaust Emissions – Spark Ignition

All vehicles
Vehicles first used on or after 1st August 1975
Basic emissions test (BET)
Full CAT test
7.4 Exhaust Emissions-Compression Ignition

Vehicles First Used Before 1 August 1979
Vehicles First Used on or After 1 August 1979
Section 8: Drivers view of the road

8.1 View to rear

8.2 Wipers and Washers

8.3 Windscreen (Classes 3, 4 and 7 only)

8.4 Bonnet

theconrodkid - 12/1/18 at 09:04 AM

that the jeep ?, what is the co at fast idle ?
first stop, air filter, then lambda sensor, you can check if it is working should fluctuate between 0-2 volts AC, if that is ok, check temp sensor resistance, if that is ok then prob the cat

ChrisW - 12/1/18 at 11:44 AM

Thanks everyone. Not sure why I couldn't find that info myself... my Google skills must have been a bit lacking yesterday!

Originally posted by theconrodkid
that the jeep ?, what is the co at fast idle ?

No, was just a random line I pulled from a failure sheet (not my vehicle). I'm doing some work with the DVSA database of MOT tests; was trying to work out what all the codes meant and if I could do anything interesting with the data.


obfripper - 12/1/18 at 11:55 AM

Just an fyi, the mot manual is changing on the 20th of may and all these codes will either change or become redundant.

Here's a link to the current draft version; pdf

There's alot of changes in structure and items covered in the new manual, it's hardly been mentioned to the trade how much is changing yet it's going live in 4 months.


ChrisW - 12/1/18 at 12:23 PM

Originally posted by obfripper
Just an fyi, the mot manual is changing on the 20th of may and all these codes will either change or become redundant.

Thanks for the heads up. Will have a read when I get a spare moment.

coyoteboy - 12/1/18 at 01:21 PM

8.1.1 is interesting. There are countless thousands of cars on the road with missing underbonnet insulation and it's horrendously expensive to replace.

froggy - 12/1/18 at 10:33 PM

Originally posted by coyoteboy
8.1.1 is interesting. There are countless thousands of cars on the road with missing underbonnet insulation and it's horrendously expensive to replace.

It’s relating more to engine covers being insecure , missing isn’t a failure