Guides
Straight answers before you ring
The questions people ask us every week, answered plainly: what a warning light means, whether the head really has to come off, and what things cost.
Warning lights and symptoms
You know something is wrong. Here is what it usually means and what to do next.
- Why is my DPF warning light on? The diesel particulate filter is full of soot and has not been able to clean itself. Often fixable, rarely a reason for a new filter.
- Why is my AdBlue warning light on? Low fluid is the easy one. If topping up does not clear it, a sensor, heater, pump or dosing injector is usually at fault.
- Do I need the cylinder head off for a seized injector or snapped glow plug? A garage quoting for head removal is not always wrong, but most seized injectors and broken glow plugs can be extracted in place with the right tools.
- How do you find an intermittent fault that shows no codes? Intermittent faults need testing while the fault is happening. Live data, wiring tests and a rolling road make that possible.
- My garage says the ECU has failed. What now? Control units do fail, but water, corrosion and wiring faults are common causes, and many units can be repaired.
Choosing between options
Straight comparisons, including when the cheaper option is the right one.
- Remap or tuning box: which is better? Both can add power. They work differently, cost differently and suit different owners. Here is a straight comparison.
- Should I repair or replace my ECU? Repair keeps your original unit and its coding. Replacement is sometimes the only option. How to tell which is right.
Question not here?
Ring reception and ask. If it comes up often, the answer goes on this page.