Nissan NV300 P0471-95 P0470 Fault Codes

For business enquiries email [email protected] Nissan NV300 Anti-Pollution System Fault: Finding a Blocked Upstream Pressure Pipe and Fixing the DPF When an anti-pollution system fault keeps coming back straight after you clear it, it usually means the van still can't trust what it's "seeing". This Nissan NV300 arrived with a warning that had survived more than a dozen trips to different mechanics, and the light returned almost as soon as the driver left the workshop. Here's how the fault was traced, proved, and fixed, from first scan to a successful regeneration and final checks. The Nissan NV300 and why this fault is so common The Nissan NV300 shares a lot with other vans in the same family, so the symptoms and fixes often overlap. This one is effectively the same platform as: * Renault Trafic (Renault version) * Vauxhall Vivaro * Opel Vivaro The customer's issue was simple but frustrating: the anti-pollution fault stayed persistent, even after repeated repairs and resets. Scanning the van with Launch X431 Euro (Launch UK) A Launch X431 Euro diagnostic tool was plugged in to start with a full vehicle scan. The tool offers a choice between Nissan and Renault, so Nissan was selected first and set to automatic search and smart detection. Meanwhile, there was another vehicle waiting (a Citroën Relay), so the scan was briefly paused and then continued. The first code: P0471-95 and live data that didn't move The main stored fault came up as P0471-95, described as pressure upstream of the turbine. Because the customer had been clearing codes on the way in, a drive test was kept in mind in case more faults appeared. On live data, the upstream pressure value sat around 1600, which is far too high (it should be roughly around 50 above atmosphere). Even with the engine running and the revs raised, the reading didn't move at all. If a sensor value stays flat when you rev the engine, treat it as a wiring, sensor, or blockage problem until proven otherwise. Proving the upstream pressure pipe was blocked Next came a hands-on check. The upstream pipe was inspected first (no obvious split), and the DPF pressure sensor was nearby. Martin removed the upstream pressure sensor, and a second sensor was tried. After that swap, the live data started behaving. Under a rev, upstream pressure showed about 59, while atmosphere sat around 15 (some systems read slightly above atmospheric). Even so, a pressure gauge test showed the real issue: the pipe itself was completely blocked, to the point it popped off during testing. With this type of fault, the system can fall back to the MAP sensor, which can hide the real cause. Two related codes showed up: P0470 and P0471 (including suffixes like -95 and -16). Faults were cleared again to get clean readings, and an engine failure hazard message appeared. In this case it related to the upstream sensor issue, not an immediate mechanical failure. A cam chain rattle was also noted. Switching to Renault data to check DPF soot levels To view soot loading properly, the diagnostic session switched to the Renault side. The key readings were: ParameterValueDPF pressure 210 mbar Soot load 62 g (maxed) That confirmed the plan: clear the upstream pipe and clean the DPF. Cleaning the pipe, adding cleaner fluid, then resetting faults Martin cleared the pipe (his favourite part, drilling) until the gauge showed it was flowing freely again. Then Launch UK cleaner fluid went in (with a small spill during fitting, quickly corrected). A batch of new faults appeared, including 200291 and 200292. An air temperature fault was also present because a sensor had been unplugged during checks, so that one was ignored. Clearing codes worked best after switching back to Renault and running a high-speed scan. Road test regeneration and the final result With the engine running, DPF pressure dropped fast, down to about 3 mbar at idle. Revs were held around 2,500 to 3,000 rpm, and then the van was driven to bring temperatures up properly. Within a short distance, soot grams started moving, and the van began its own regeneration, hitting just under 600°C. Some smoke appeared during the process, then eased as the clean-out completed. Final checks showed around 3.5 g soot and roughly 4 mbar at idle, with no fault codes remaining. The win isn't just clearing the light, it's confirming pressure and soot numbers return to normal. Finishing up with a service Once the engine was running correctly, the van moved on to a routine service, including: * Filters * Oil * Drop links With the anti-pollution fault resolved and the DPF readings back where they should be, the NV300 was ready to go back into daily use.