The NEW Aftermarket Magazine Troubleshooter quiz – November 2026
16 October 2026 
Think you know your diagnostics? Put your fault-finding skills to the test with the Aftermarket Magazine Troubleshooter quiz. Each issue, in partnership with DiagnoseDan TSB (DDTSB), we’ll give you a real-world diagnostic challenge. Study the evidence, work out what’s really going on and tell us what you think is causing the fault.
Get the Aftermarket Troubleshooter challenge right and you could earn something money can’t buy: an Aftermarket Troubleshooter mug.
Yes, a mug. But not just any mug.
These are won, not bought and are only available to winners of the Aftermarket Troubleshooter quiz. So when it appears on your toolbox, desk or tea round, everyone in the workshop will know you’ve earned it.
And there’s more than bragging rights at stake. Each issue’s winner will also receive a six-month subscription to the DDTSB technical bulletin database, worth €230 + VAT.
This month’s challenge
A 2018 Peugeot 3008 1.5 BlueHDi arrives with the Urea warning light illuminated and “No start in 1000 km” displayed. The ECM stores P20E8 00 – Urea Fluid Pressure too Low.
The Urea level is adequate, and no external crystallisation or leakage is found. With the ignition ON, scan-tool live data shows 4.0 bar.
With the engine at operating temperature, a mechanical pressure gauge is connected between the Urea supply line and injector. The technician activates “DeNOx system pressurization control.”Pressure reaches 6.0 bar, but once the pump stops it drops to 3.2 bar within 3 minutes. During the lower part of the pressure drop, scan-tool live data remains fixed at 4.0 bar.
What should the technician do next?
A) Replace the Urea tank due to a faulty internal pressure sensor.
B) Disconnect the pressure gauge from the Urea injector, block one pipe connector on the gauge, so it remains connected only to the pipe from the tank and repeat the pressure test.
C) Replace the Urea tank/pump because the pressure drop confirms an internal leak.
D) Perform “Reinstallation of DeNOx System Fault” before carrying out further pressure testing.
Think you’ve cracked it?
Submit your answer and details in the form below and if you are correct, you’ll be entered into the draw .
Entries for this issue close at 11.59pm on 23 November 2026. All correct entries will go into the draw, and one winner will receive: The exclusive Aftermarket Troubleshooter mug – you can’t buy it; you have to earn it. A six-month subscription to the DDTSB technical bulletin database, worth €230 + VAT.
We’ll reveal the correct answer on this page shortly after entries close, together with an explanation of the diagnosis. The answer will also appear in the next issue of Aftermarket, and the winner will be contacted by email.
Competition terms
One entry per person. One winner will be selected at random from all correct entries received before the closing date and contacted using the email address supplied with their entry. No cash alternative is available and prizes are non-transferable. The editor’s decision is final. By entering, entrants agree to their name and/or business name being published in Aftermarket and on the Aftermarket website if selected as the winner. Full competition terms and conditions are available on the Aftermarket website.