A generic OBD scanner will tell you P155168 is a barometric pressure sensor fault. On a 2015 Volvo V60 II, it actually means the engine control module is unhappy with the injector circuit on cylinder one. The technician had just replaced the injectors on cylinders 1, 3, and 5. Right after the replacement, this code appeared, bringing the job to a sudden halt.
The generic scanner trap
Generic code databases automatically translate P155168 as 'Barometric Pressure Sensor Circuit Short to B+'. On the 5-cylinder diesel running a Bosch EDC17 module, Volvo's VIDA system defines ECM-P155168 as an implausible signal or performance issue on the cylinder 1 injector circuit. The subcode 68 points directly to an algorithm-based performance deviation. If a technician follows the generic definition, they will waste hours testing the barometric pressure sensor wiring when the actual fault is sitting on the injector rail.
Missing injector calibrations
Because the injectors are new, our diagnostic platform ranked missing IMA/IQA coding as the most likely cause at 85 percent probability. The 7 to 8 character calibration codes for the new injectors must be programmed into the ECM. Furthermore, the zero fuel calibration adaptations must be reset. The ECM continuously monitors the current profile and injection quantity. If the saved profile does not match the physical characteristics of the newly installed hardware, the module sets the fault code.
Physical wiring risks during replacement
If the coding is correct, the next highest probability at 70 percent is mechanical damage to the wiring harness. Replacing injectors on cylinders 1, 3, and 5 requires moving the harness that runs close to the fuel pipes and valve cover. This creates a high risk of pinching wires against sharp edges, damaging the insulation, or pushing back the pins inside the connectors for injectors 1 and 5. The Bosch driver monitors continuity millisecond by millisecond, so even slight contact resistance triggers a code.
Verifying the hardware
At 55 percent probability, the replacement injectors themselves might be incompatible. The Euro 6 engine requires very specific electrical and hydraulic parameters. An incompatible part number or wrong generation of piezo/solenoid will cause the ECM to detect incorrect impedance or charge times.
Next steps for the bay
Stop chasing the barometric pressure sensor. Start by verifying that the IMA/IQA codes are programmed into the ECM, reset the adaptations, and check the live cylinder balance on idle. Have you seen generic OBD definitions send your technicians down the wrong diagnostic path like this?