This code indicates that no boost pressure is being detected where expected — i.e., the turbo is not generating or delivering pressure correctly. This could be due to:
a boost leak (somewhere post-turbo),
control system failure (e.g. VGT actuator or vacuum issue),
sensor-related issue (MAP, boost pressure sensor),
or exhaust backpressure/turbo not spinning.
You’ve replaced the turbo, tested vacuum, replaced the MAP sensors, and ruled out the EGR system and exhaust pressure sensor.
High Probability Causes (even after turbo swap):
Charge Air Leak or Split Hose / Intercooler Crack
After turbo replacement, were all intercooler hoses and clamps pressure-tested?
A split intercooler, cracked plastic end tanks, or bad connections at the intercooler are very common causes of P2262.
Even a small leak here will prevent boost pressure from building, and exhaust soot + high fuel consumption follow.
Boost Pressure Sensor Fault or Wiring
The boost sensor may be reporting 0 boost even if pressure is present.
You already swapped MAP sensors (good). But:
Was the boost pressure sensor tested live (not just swapped)?
Check wiring continuity between sensor and ECM. French cars often suffer from rodent damage or brittle loom sections.
VIDA “showed nothing useful” — that might mean it’s receiving constant (invalid) data.
VGT (Variable Geometry Turbo) Actuator Fault
Your D5 engine has an electronic actuator on the high-pressure (HP) turbo.
If the actuator fails to position vanes correctly, turbo won’t spool = no boost.
Even a new turbo will behave this way if the actuator:
was not replaced (if reused from old turbo),
was misaligned, or
has connector / CAN bus issues.
VIDA should show actuator position request vs actual. If those don’t match, actuator fault or wiring.
DPF Blockage or Severe Exhaust Restriction
A clogged DPF (even partially) can cause turbo stall or low spool = no boost.
Symptoms:
Boost issues at all revs.
Slow RPM climb.
High fuel consumption.
Hot EGTs and poor performance.
VIDA should show DPF soot load and pressure differential. If not checked, have the DPF flow tested.
Live data session with VIDA: You must look at:
Boost pressure requested vs actual
Actuator vane position requested vs actual
Exhaust pressure (pre/post DPF)
Air mass (MAF) values
EGR flow vs expected (even if EGR is new)
Vacuum levels while driving, not static
Smoke test from turbo outlet forward: Many garages only smoke the intake — you need a smoke test from the turbo through to the intercooler and intake manifold. Any minor leak will prevent boost build-up.
Exhaust backpressure test: Confirm the DPF is not partially clogged.
Inspect all charge pipes and intercooler for cracks or leaks — even tiny ones. Pressure test the intake system.
Check boost pressure sensor and wiring — live readings via VIDA; multimeter test if needed.
Confirm if actuator was new. If reused, test actuator with diagnostic tool or manually. Also check wiring/connectors to the turbo actuator.
DPF flow check — or test backpressure with a gauge at the EGR pressure sensor port.
P2262 with a new turbo almost always means a downstream leak, actuator fault, sensor issue, or exhaust restriction.
VIDA may not throw specific codes for a clogged DPF — just symptoms like your current ones.