Keep the complete code description
A report may refer to flow, a circuit or system operation. Send the controller and full description rather than treating the component name as a confirmed diagnosis. Include any accompanying running concern.
Explain earlier repairs
List valve, cooler or related work and whether the symptom changed. If the warning returned after a repair, say how soon. Accurate history helps the workshop plan the checks around the current concern.
Include the normal vehicle use
Tell us the engine, transmission and journey pattern, plus existing tuning. If remapping is also requested, describe it as a separate objective after the unresolved fault.
Use the warning history guide to prepare the report and discuss an EGR appointment.
Mobile Stage 1 and ECU solutions, or workshop chassis dyno tuning