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Mitsubishi ASX 2.2 DPF Faults and Oil Dilution Fix

Mitsubishi ASX 2.2 DPF Faults and Oil Dilution Fix If your Mitsubishi ASX 2.2 keeps forcing DPF regens and the oil level keeps climbing, the warning lights are only the surface of the problem. This 2017 diesel arrived after an oil change, yet the faults were still active and the car was reportedly regenerating on nearly every trip. The checks soon pointed to a familiar pattern on these engines: oil dilution, odd DPF pressure readings, and leaks that can push the whole system in the wrong direction. That made this less about clearing codes and more about proving what the car was doing. Why this ASX kept bringing the warnings back This ASX had the usual reputation problem attached to it. Japanese diesels often get a free pass for reliability, but this 2.2 unit is known for repeated faults, including: * rising oil level from oil dilution * cracked exhaust manifolds * split boost hoses With the Launch tool updating, a Mucar 892BT scan tool was used instead. available from.. https://mythinkcar.com/?ref=dnnktcax discount code JIMMYORILEY The main engine codes were P2454, for the DPF pressure sensor, and P252F, for engine oil level too high. There was also a low-voltage fault, but that was not relevant here. Live data told the bigger story. The last regeneration had happened only 17 minutes earlier, which matched the complaint that the car was trying to regen constantly. What the pressure readings revealed The DPF pressure reading did not make sense from the start. With the engine off, it should sit at 0 hPa. At idle, it should usually be around 2 to 10 hPa, with roughly 5 hPa being a healthy figure. This one dropped to minus 5 hPa with the engine off and showed far too much pressure at idle. A sensor calibration was attempted through the special functions menu, but it made no difference. A visual check then showed the pressure sensor had already been replaced and looked new. After that, a manometer was connected to compare actual exhaust pressure with the scan data. The sensor reading was still not exact, although it was not wildly wrong either. That matches a problem often seen on some Mazda, Nissan, Toyota, Hyundai, Kia and Mitsubishi diesels, where the reading never looks quite right even after fitting a new sensor. The oil level and leaks mattered as well The dipstick showed the oil sitting above the maximum mark, even though the oil had apparently been changed the day before. On these engines, filling right to max is asking for trouble. Midway between the marks leaves some room before dilution pushes it too high. A smoke pressure test then uncovered two more faults. There was a major injector seal leak on injector number two, plus a wet hose that pointed to a slow long-term leak rather than a fresh split. Both faults could add to DPF trouble, so they still needed repair. Cleaning the DPF and resetting the ECU At around 95,000 miles, ash build-up was already a strong suspect. Removing the DPF on this model is a big job because it sits behind the engine, so an on-car chemical clean was tried first. The target was clear: below 50 hPa at 3,000 rpm and roughly 5 hPa at idle. After cleaning, it came back to about 50 hPa at 3,000 rpm and 5 hPa at idle, then held those figures on a road test of roughly 6 to 8 miles. Changing the oil alone will not clear the oil dilution warning on this ASX. The ECU also needed two resets: Engine Oil Exchange Service and DPF Exchange Service. Only after those initialisations were completed did the fault codes clear properly. Final thoughts The biggest lesson from this ASX is simple: data matters more than dashboard lights. The car needed pressure checks, leak checks, a DPF clean, and the correct service resets before the faults would stay away. It also ended with a blunt verdict. If you're buying an older diesel, the Mitsubishi ASX 2.2 and Mazda 2.2 SkyActiv are two models worth approaching with care. for business enquiries email [email protected] www.orileysautos.com