How to run a diesel diagnostic appointment

A diesel diagnostic appointment works best when the symptoms are collected before the vehicle arrives, the time is booked as diagnosis rather than repair, and the client agrees to a quote before any parts are replaced. Ask what the driver noticed and when, read the fault codes, reproduce the problem on a test drive if you can, and check the systems that cause trouble on modern diesels: injection, turbo, exhaust gas recirculation and particulate filter. Then explain your findings plainly and give a price for the repair.

These answers save time on the bench and help you decide how long to book. An intermittent fault that only appears after an hour of work needs a longer slot than a fault code that's always present.

Reading a fault code is the start, not the answer. A code points to a system; finding the cause can mean checking wiring, sensors, pressures and the history of the vehicle. Explain to clients that diagnosis is charged as time, separately from the repair, so they don't expect a free code reading to tell them what part to buy.

Particulate filters, recirculation valves and exhaust after-treatment can cause power loss and warning lights, and are affected by how the vehicle is used: repeated short trips can stop a filter from cleaning itself. Ask about the driving pattern before recommending a cleaning or a part, and explain what the driver can change.

Water in the fuel, the wrong fuel or contaminated tanks cause symptoms that look like injection faults. Check the fuel filter and water separator early, and ask where the vehicle was last filled up. Finding contamination before replacing injectors saves the client a large bill.

Don't start a repair beyond the agreed diagnosis without the client's approval. For fleet clients, agree in advance the amount you can spend without calling, and call above it. A short written quote by message avoids disputes when the bill arrives.

Clear the codes, test drive again under the conditions that caused the fault, and tell the client what to watch in the following days. If the fault returns, a short follow-up check is easier to plan when it was agreed at handover.

Some machines can't easily come to the workshop. A diagnostic visit on site with a portable tester can find the fault and let you bring the right parts on the next visit. Charge travel clearly, and ask for photos of the dashboard, the warning lights and the problem area before you go.

On Book, each service has a name, a price and an optional description shown on your public page. Create a "Diesel diagnostic" service, and a longer "Intermittent fault diagnostic" service for faults that are hard to reproduce. Clients pick a slot and book with their name, email and phone, and describe the symptoms, warning lights and vehicle in the optional note, which you read in your new-booking email before the vehicle arrives. In the description, say that diagnosis is charged separately from any repair and that you'll quote before repairing.

Durations and prices are examples: set your own. If you need to move an appointment, reschedule it from your bookings list and tell the client yourself, since Book doesn't email clients about changes. Book costs €5/month, everything included: unlimited services and bookings, no commission, no contract.