WLTP, Delays and withdraws.

We have been beset with vehicle updates, lengthy build times and vehicles suddenly being withdrawn from the Scheme, some of which reappear after only a few days. The bulk of the problems can be attributed to the new WLTP testing (Worldwide Harmonised Light Vehicle Test Procedure). The change to the way cars are tested has been planned for a number of years but accelerated in implementation due to the number of scandals, particularly surrounding VW, and this fast-track has caused a lot of panic, confusion and delays for customers. We will run through the changes happening.

What is WLTP?

The vehicles are tested in labs, as with the outgoing NEDC tests but are longer, up from 20 minutes to 30 minutes, and represent a closer reflection to real world driving to measure fuel consumption and CO2 levels:

  • More realistic driving behaviour;
  • A greater range of driving situations (urban, suburban, main road, motorway);
  • Longer test distances; 23.25km compared to 11km
  • More realistic ambient temperatures, closer to the European average; tested at 14 degrees and 23 degrees
  • Higher average and maximum speeds; Average speed 46.5km/h compared to 34km/h
  • Higher average and maximum drive power;
  • More dynamic and representative accelerations and decelerations;
  • Shorter stops; only 13% of test at standstill compared to 25% previously
  • CO2 values and fuel consumption are provided for individual vehicles as built;
  • Stricter car set-up and measurement conditions;
  • Enables best and worst-case values on consumer information, reflecting the options available for similar car models.


Worldwide Harmonised Light Vehicle Test Procedure is being implemented in four stages:

Step 1 – September 2017 – All new models and engines released after this date will have to be tested to WLTP

Step 2 – September 2018 – All cars sold/registered will have to have been tested. *An exception for end-of-series vehicles to allow for a limited number of unsold vehicles in stock that were approved under the old NEDC test to be sold for one more year.

Step 3 – September 2019 – Real Driving Emissions (RDE), Vehicles are tested on the open road for 90-120 minutes to establish pollutants. The first stage of RDE  allows a car to emit 2.1 times the amount of NOx during testing.

Step 4 –  The second stage of RDE – known as step 2 or RDE2 – allows the car to emit 1.5 times the amount of NOx, and will become mandatory for new type approvals in January 2020, then all new registrations from January 2021. Until the end of 2020, both WLTP and NEDC values will be calculated for all vehicles. These values will be contained side by side in the vehicle papers with effect from the respective vehicle certification. From 2021, the WLTP values will be the only consumption/emissions values for all cars



WLTP tests are carried out on every trim line with every modification avaialble for sale, for example, alloy wheels may cause a decrease in weight, while a better audio system may add to a vehicle’s total mass. Options such as cruise control can also affect engine performance either improving or increasing emissions. Manufactures have in responce trimmed the number of lines and optional extras avaialble, and in some cases dropped engines from the range in order to get the tests completed in time for September 2018.

The delays will increase as we move closer to the deadline, Volkswagen have stated that they are pulling some engines quoting:

“By 1 September, everything needs to be fixed, done and certified. That’s all of our portfolio, and our portfolio is big. We’re not prepared for new certification for all of our cars in one year, with access to test benches, equipment, wind tunnels and so on, and it’s the same for our suppliers. Now, it’s all in a couple of months. We need more time, more test benches, more people at the [test] authorities. Some engines will not be available for two months or so. We have solutions but not the tests available. So in some cars, we will not have all the engines.”

In contrast Volvo have completed their testing quoting:

“Volvo welcomed the new WLTP testing methods when they were first announced, as greater transparency in areas such as fuel consumption and emissions helps customers make better informed buying decisions. We are pleased that we are the first to sell a complete range of cars that meets the new testing standards.”


WLTP Results

Vauxhall have released some results from their WLTP testing and as results from the Astra show the MPG figures are a little more realistic:

1.4 (100PS), Manual 5-speed 37.7 67.3 31.4 52.3
1.0 (105PS) Turbo S/S ecoFLEX, Manual 5-speed 54.3 74.3 38.7 58.9
1.0 (105PS) Turbo S/S ecoFLEX, Easytronic 54.3 78.5 34.4 60.1
1.4 (125PS) Turbo, Manual 6-speed 38.7 64.2 30.1 50.4
1.4 (150PS) Turbo, Manual 6-speed 38.7 62.8 29.1 49.6
1.4 (150PS) Turbo S/S, Automatic 39.2 64.2 28.5 48.7
1.6 CDTi (110PS), Manual 6-speed 67.3 85.6 44.1 65.7
1.6 CDTi (110PS) S/S ecoFLEX, Manual 6-speed 72.4 91.1 49.6 67.3
1.6 CDTi (136PS) S/S, Manual 6-speed 61.4 83.1 46.3 65.7
1.6 CDTi (136PS), Automatic 6-speed 49.6 76.3 36.2 61.4