SAIC Maxus Deliver 9 P226D09 Diesel Particulate Filter Malfunction & P244B00 DPF Pressure Too Large

SAIC Maxus Deliver 9 DPF Fault P226D09 Fixed Thinking about a SAIC Maxus Deliver 9 because it is cheaper than a Transit, but worried about reliability, especially around the DPF? Here is a real-world case from a 2022 rental van that came in with low power and a stubborn DPF fault. It was the first time working on one, which made it a good chance to see how these vans are put together and what common issues might show up. Dash check: AdBlue, MPG and warnings Inside, the basics looked healthy: * AdBlue level was shown as 65%, which is handy, since many vans only warn when it is low. * The trip computer showed an average of about 34 mpg. * No engine warning light was on at that moment. The customer had already cleared the fault codes, which is why nothing was showing on the dash. What the fleet manager had already tried The van came from a manager who looks after a fleet and has his own Snap-on diagnostic kit. To keep the van moving, he had: 1. Deleted fault codes whenever it went into limp mode. 2. Poured DPF cleaner into the fuel tank. 3. Paid someone to try cleaning the DPF on the vehicle. The problem always came back, and power kept dropping, so it needed a proper diagnosis rather than more additives. Plugging in the Launch X431: fault codes A Launch X431 Euro scan was run, with the vehicle identified as a 2022 Deliver 9 from China. There were a few minor historic codes, likely from a flat battery, and a stored AdBlue tank empty code, although the tank now showed about 63% full. The big one was P226D09: diesel particulate filter removed or malfunctioned. That usually points to a pressure problem at the DPF, sometimes caused by a cracked filter or faulty sensor readings. Live data and the clue in the numbers Looking at the DPF data stream showed some odd figures: * DPF differential pressure was shown as 65 bar, or 65,535 mbar, which is physically impossible. * Measured soot mass was only 8.6 g. * When the engine was revved to around 3,000 rpm, the pressure reading actually dropped slightly. With the engine stopped and ignition on, the pressure sensor returned to zero, so the sensor itself was talking to the ECU. The crazy value pointed to a problem in how it was reading pressure, rather than a real 65 bar in the exhaust. Likely causes were: * Software glitch * Faulty DPF pressure sensor * Damaged or split DPF pressure hoses Finding the damaged DPF pressure hose Under the van, the DPF was easy to spot and looked huge, with no visible cracks. Near it sat the DPF pressure sensor with two red hoses running down to the exhaust. Straight away, there was an obvious issue. The hose was effectively burst and no longer sealed. A length of sturdy braided fuel hose was cut and used to replace the damaged pipe. Once fitted and secured, the live data immediately looked more believable, with around 107–108 mbar of pressure at idle. Cleaning the blocked DPF properly With the hose sorted, a new code appeared: P244B: pressure difference too large in the DPF. In plain terms, the DPF was blocked. It is hard to say which came first. A blocked DPF can raise pressure and burst weak hoses, and a burst hose stops regenerations and lets soot build up. To make things worse, the original hoses are a kind of biodegradable material that softens with age and heat. A professional DPF clean was carried out on the vehicle using a Launch UK DPF cleaning gun: * The new hose was connected to the gun, filled with cleaning fluid. * The gun was set to about 120 psi and the fluid was injected into the DPF. * The engine was started and held at around 2,800–3,000 rpm while the cleaner worked through. During this, the pressure readings dropped from very high figures down towards normal values. Engine speedExpected DPF pressure. Idle2–6 mbar 3,000 rpm 30–60 mbar After the clean and some controlled revs, the van settled at about 2–3 mbar at idle and around 29–31 mbar at higher revs. Final readings and road test The fault codes were cleared and none came back. There were no “end of life” messages for the DPF, so there was no need to tell the ECU a new filter had been fitted. On the road, the Deliver 9 felt surprisingly nippy and pulled well. The engine would now rev freely where it had felt strangled before. There is a manual DPF regen button on the dash, but pressing and holding it did nothing, likely because the ECU did not request a regen at that time. Unlike some Toyotas, there was no on-screen DPF fill percentage. A final scan after the test drive showed no DTCs, and pressures stayed low. all sorted. contact [email protected] www.orileysautos.com