MC Tech Solutions

Tag: citroen c4 grand picasso

  • Reading fault codes with a cheap OBD2 scanner

    A warning light on the dash used to mean a trip to the garage just to find out what it meant. Now a €15 adapter and your phone can tell you, and often point you to a fix you can do yourself.

    What is OBD2?

    Every petrol car sold in the EU since 2001, and diesel since 2004, has an OBD2 (on-board diagnostics) port. It’s a 16-pin socket, usually under the dashboard near the steering column. Plug a reader in and you can see:

    • Fault codes stored by the engine computer, like P0401
    • Live data: coolant temperature, boost pressure, fuel trims, sensor readings and more
    • Readiness monitors, which show whether the car’s self-tests have completed

    What you need

    • An ELM327-style adapter (Bluetooth or Wi-Fi). They’re cheap, but quality varies a lot. Cheap clones can be unreliable, so buy one with good reviews.
    • An app: for example Car Scanner ELM OBD2 or Torque Pro on Android, or Car Scanner on iPhone.

    Reading a code, step by step

    1. Plug the adapter into the OBD2 port, and turn the ignition on (engine off or running).
    2. Connect the app to the adapter and run a scan.
    3. Write down every code, plus the freeze frame data if the app shows it: a snapshot of the conditions when the fault happened.
    4. Look the code up for your specific car and engine. Owner forums are gold here.
    5. Fix the cause, then clear the code and check that it doesn’t come back.

    Example: P0401 on a diesel

    P0401 means “EGR flow insufficient”. It’s common on diesels, where the exhaust gas recirculation valve and pipes clog with soot. The code doesn’t mean “replace the EGR valve”; it means the computer saw less flow than expected. Cleaning the valve, checking the pipes and vacuum lines, or a long run might sort it. This is why you research the code rather than just throwing parts at it.

    The limits of a cheap scanner

    Generic OBD2 mostly covers engine and emissions faults. ABS, airbags, the electronic parking brake, DPF regeneration and service resets usually need manufacturer-level software:

    • Citroën and Peugeot (like my C4 Grand Picasso): Diagbox with a compatible interface
    • Volkswagen Group (like the A4 I had): VCDS or OBDeleven
    • Ford (like the S-Max I had): FORScan, which works with some modified ELM327 adapters

    These can read every module in the car, run tests and do jobs like coding or forcing a DPF regeneration.

    Don’t just clear codes

    Clearing a code turns the light off, but it doesn’t fix anything, and the light will come back. Clearing codes also resets the readiness monitors, which is a giveaway that something’s been hidden. Use the scanner to understand the problem, not to hide it.

  • Changing your oil and filters at home

    An oil and filter change is the best first job for DIY car maintenance. It’s simple, it’s satisfying, it saves money, and it’s the single most important thing you can do for an engine’s lifespan. Here’s how I do it.

    Get the right oil

    This matters more than anything else. Modern engines, especially diesels with a DPF, need oil that meets a specific manufacturer approval, not just the right thickness:

    • VW Group “Pumpe Düse” diesels like the 1.9 TDI AWX in the A4 I had need oil meeting VW 505 01. These engines have a reputation for being bulletproof, but the wrong oil wears the camshaft.
    • Citroën and Peugeot HDi diesels with a DPF, like my C4 Grand Picasso’s 1.6 HDi, typically need a low-ash oil meeting PSA B71 2290.
    • Fords like the S-Max list a Ford WSS specification.

    Your handbook gives the exact spec and capacity. Check the bottle lists that approval, not just “suitable for”.

    What you need

    • The correct oil, and a new oil filter for your exact engine
    • A new sump plug washer. They’re crush washers, designed to be used once.
    • Drain pan, filter tool, socket for the sump plug, torque wrench, funnel, gloves and rags
    • Jack and axle stands, or ramps

    Step by step

    1. Warm the engine for a few minutes. Warm oil drains faster and carries more dirt out with it. Don’t get it hot.
    2. Raise the car safely on axle stands or ramps, on level ground, with the handbrake on and wheels chocked.
    3. Remove the oil filler cap. It helps the oil drain.
    4. Drain the oil. Undo the sump plug (watch out, the oil is warm) and let it drain fully.
    5. Change the filter. Remove the old filter, wipe the housing clean, and fit the new one with a smear of fresh oil on the seal. For cartridge filters, like on the 1.6 HDi, replace the housing’s O-rings too.
    6. Refit the sump plug with a new washer, tightened to the specified torque. Overtightening strips the sump threads.
    7. Refill with slightly less than the stated capacity, wait a minute, and check the dipstick. Top up to just below the max mark.
    8. Run the engine for a minute, check for leaks around the filter and plug, then switch off, wait, and recheck the level.
    9. Reset the service indicator. The procedure is in the handbook, or use a diagnostic tool.

    While you’re there: the other filters

    • Air filter: usually just clips or screws in the airbox. A clogged one hurts performance and economy.
    • Cabin (pollen) filter: keeps the air inside the car clean and the windows clear. It’s often behind the glovebox.
    • Fuel filter (diesels): less frequent, but important. After changing it, the fuel system must be primed, and many diesels have a hand primer bulb for this. Follow the procedure for your car, because air in a diesel fuel system can stop it starting.

    Get rid of the old oil properly

    Never pour it down a drain. Put used oil back in the empty containers and take it, with the old filter, to your local civic amenity site. Check with your council what they accept.

    How often?

    Follow the service schedule in your handbook, but for older diesels that do a lot of short trips, changing the oil more often than the maximum interval is cheap insurance. Oil is a lot cheaper than an engine.

  • A basic DIY car maintenance tool kit

    I do as much of my own car maintenance as I can. Over a few cars, including the Citroën C4 Grand Picasso I drive now, a Mk1 Ford S-Max and an Audi A4 1.9 TDI before that, I’ve learned which tools earn their keep. Here’s the kit I’d recommend for someone starting out.

    Safety first (don’t skip this section)

    • Trolley jack rated well above your car’s weight
    • Axle stands, a pair at least. Never work under a car held up only by a jack.
    • Wheel chocks for the wheels staying on the ground
    • Nitrile gloves and safety glasses. Oil, brake fluid and grit in the eye are no fun.

    The core kit

    • Socket set: a good 3/8″ drive set covers most jobs, with a 1/2″ drive set for bigger bolts. Make sure it has deep sockets and extensions.
    • Breaker bar: for stubborn wheel nuts and crank bolts.
    • Torque wrench: wheel nuts, sump plugs and caliper bolts all have torque specs. Too loose is dangerous, and too tight strips threads.
    • Combination spanners: 8 mm to 19 mm covers most cars.
    • Torx and hex bits: French and German cars use Torx everywhere. My C4 and the A4 were full of them.
    • Screwdrivers, pliers and a set of trim tools for interior panels without breaking clips.

    For servicing

    • Oil drain pan big enough for your engine’s full capacity
    • Oil filter tool: a strap, claw or cap-type wrench. Some engines, such as the 1.6 HDi in my C4, use a cartridge filter in a plastic housing, so you need the right socket for the cap.
    • Funnel, rags and a roll of blue paper
    • Brake bleeding kit: a simple one-man bleeder makes brake fluid changes easy

    For diagnosis

    • OBD2 scanner: a cheap Bluetooth adapter and a phone app reads fault codes on any modern car. See reading fault codes with a cheap OBD2 scanner.
    • Multimeter: for checking batteries, fuses, bulbs and sensors
    • Inspection light: a rechargeable LED torch or work light
    • Battery charger or jump starter

    Brand-specific extras

    • Volkswagen Group (Audi, VW, Skoda, SEAT): triple-square (XZN) bits for some bolts, plus a VCDS cable or OBDeleven for proper diagnostics
    • Citroën and Peugeot: plenty of Torx, and a Diagbox-compatible interface for full diagnostics
    • Ford: FORScan with a compatible adapter works wonders on cars like the S-Max

    Nice to have

    • A kneeling pad or creeper
    • Penetrating oil for rusty bolts
    • Magnetic pick-up tool for the bolt you will drop
    • A Haynes manual, or workshop info for your exact car

    Start small

    You don’t need everything on day one. Start with the safety kit, a socket set and a torque wrench, then buy tools as jobs come up. Good first jobs are changing oil and filters, swapping bulbs and wiper blades, and preparing for the NCT.