A 2016 Volvo V40 II is cranked over in a bay, but the engine will not catch, and the only clue is a P22907B fault code pointing to fuel pressure. The technician wrote a simple note on the ticket: "bilen startar inte". The car does not start.
When we see this specific code on a Volvo VEA engine, it usually points to a failure to reach the critical starting fuel pressure. The engine control module needs to see a minimum threshold before it will even attempt to pulse the injectors. If the pressure falls short, the module logs P22907B and completely locks out injector activation to protect the system.
In the diagnostic platform we build, we analyzed this exact scenario. The data pointed to four distinct physical causes, all heavily influenced by recent physical work on the fuel system. Here is exactly how the diagnostic path breaks down.
Trapped air in the high-pressure circuit
Our engine ranked air in the system as the most likely culprit at 75 percent. This almost always happens after the fuel injectors and high-pressure pipes have been removed for a gasket change. A modern common rail high-pressure pump, like the one on the Volvo VEA D4204T8 engine, simply cannot compress air to build up the necessary starting pressure. That baseline pressure is normally at least 200 to 250 bar.
If the system is not properly bled, the air trapped inside acts like a mechanical spring. The high-pressure pump strokes, compresses the air pocket, and the actual pressure in the rail barely moves. The engine control module registers that the pressure is not reaching the starting threshold within the prescribed time limit. It then sets the P22907B code and shuts down the injection sequence entirely.
To prove this out, you need to look at live data during engine cranking. Set your scan tool to display actual rail pressure versus desired rail pressure. If the actual pressure stays completely flat or climbs at a crawl while the engine turns over, you have an airlock. The fix requires forcing a bleed of both the low-pressure and high-pressure circuits. You can do this using a manual vacuum pump or by commanding the electric feed pump through your diagnostic tool.
Internal return leaks from damaged injectors
The second most likely cause, coming in at 55 percent, is an internal return leak in one or more injectors. When technicians remove injectors to replace copper seals, the injectors face significant mechanical stress. Using a slide hammer to pull a stuck injector out of the cylinder head can easily apply lateral forces that damage the internal tolerances of the component. Furthermore, microscopic dirt can enter the inlet during the job.
If an injector needle sticks, an internal seal gets damaged, or the control valve fails to seat perfectly, fuel leaks uncontrollably straight out into the return line. The high-pressure pump is trying to build that 250 bar minimum, but the fuel is simply bypassing the rail and draining back to the tank. The engine will never start under these conditions.
The diagnostic step here is a physical leak-off test. Connect measuring glasses to the return ports and crank the engine. If one glass fills up rapidly while the others stay nearly empty, you have found the leak. If the mechanical condition of the injectors is suspect, they need to be pulled and tested on a proper bench.
Wiring faults at the rail pressure sensor
Ranked at 40 percent is a purely electrical issue. When replacing injector seals on a VEA engine, you have to move the wiring harness and unplug the pressure sensor to get clearance. The injectors themselves also have internal i-ART connectors that require careful handling during disassembly.
If the connector to the rail pressure sensor is not pushed in until it clicks into a fully locked position, or if a pin has backed out of the connector housing, the engine control module will read a voltage corresponding to zero bar. It thinks there is no pressure at all. The same applies if the harness was damaged or pinched under a high-pressure pipe during reassembly.
Before tearing the physical fuel system apart again, test the sensor electrically. Check the signal voltage with a multimeter with the key on and the engine off. Then perform a visual inspection and a pin tension test on the connector terminals. A backed-out pin or a lack of drag on the terminal will cause a hard fault every time.
A sticking fuel pressure regulating valve
The final primary cause, ranked at 30 percent, involves the suction control valve or pressure control valve. Opening any part of a common rail system introduces the risk of contamination. Particles of soot or dirt from the injector wells can easily fall into the open lines when fittings are loosened.
Once that dirt reaches the high-pressure pump or the rail, it can plug the micro-screen or wedge the regulating valve in the open position. When the valve is physically jammed open, all the fuel volume the pump creates is immediately dumped back to the tank. The system pressure will never exceed the baseline feed pressure from the tank pump.
You can spot this in live data by monitoring the regulator duty cycle percentage while cranking the engine. If the duty cycle goes to its maximum command state but pressure does not rise, the valve is either stuck or blocked. The next step is to remove the valve and perform a detailed visual check of the micro-screen and O-rings for debris.
Tracking the physical evidence
A no-start condition on a common rail diesel often looks like a catastrophic pump failure at first glance. But when you look at the sequence of events, a P22907B code is usually the result of a microscopic error during reassembly. Whether it is an unbled line, a damaged internal seal, a backed-out pin, or a grain of soot in a regulating valve, the evidence is always measurable. Look at the actual versus desired pressure, run the leak-off test, and check the duty cycle before you order hard parts. I would be curious to hear if other shops are seeing a spike in these self-inflicted fuel pressure faults after routine seal replacements.