Diagnostics-first • Root-cause fixes
📞 07966389617 ✉️ contactus@smartmerks.co.uk

Diagnostics & fault-finding

Warning lights and limp mode aren’t “replace this part and hope”. Proper diagnostics means testing, proving the fault, repairing correctly, and verifying the fix.

What I diagnose

Commercial vehicles are complex — especially emissions systems and networked electronics. I specialise in the issues that waste time and money when guessed.

  • ✅ Limp mode, reduced power, turbo/boost control issues
  • ✅ DPF/EGR faults, soot loading, regen strategy issues
  • ✅ AdBlue/SCR: NOx sensors, dosing faults, countdown warnings
  • ✅ Electrical faults, battery drains, alternator/charging issues
  • ✅ CAN communication errors, module faults, wiring issues
  • ✅ Intermittent faults that “come and go”
Diagnostics session
Scan + symptom verification + guided testing + a clear outcome/quote.
Evidence-based
Live data, actuator tests, wiring checks and component validation before replacement.
Verification
Post-repair checks and road test (where applicable) to confirm the issue is resolved.
Note: Some faults require time-based testing. You’ll be kept informed before any extra time is spent.
Book diagnostics

Help me help you

Include: vehicle model/year, mileage, when the fault occurs, and any dashboard messages.