MAP sensor performance on Mercedes — OM651 diesel boost sensor and M271/M274 petrol intake sensors both fail with mileage.
Mercedes-Benz P0106 — MAP sensor performance on Mercedes — OM651 diesel boost sensor and M271/M274 petrol intake sensors both fail with mileage. Typical UK independent garage cost: £140–£480.
What actually causes P0106 on a Mercedes-Benz
OM651 diesel boost sensor (mounted in the charge pipe) suffers contamination from EGR soot blowing back through a leaking EGR cooler — clean it, or replace if signal is permanently drifted. M271 Kompressor petrol has a long history of intake manifold flap problems that present as P0106. M274 modern turbo petrol fails the sensor by 80k miles.
Mercedes-Benz engines that log P0106
- OM651 2.1 diesel (C/E/GLK)
- M271 1.8 Kompressor petrol
- M274 2.0 turbo petrol (C/E/GLA/CLA)
- M276 3.0 V6 biturbo
How we diagnose P0106 on a Mercedes-Benz
- Xentry — read MAP/boost sensor live data vs commanded
- On OM651, pressure-test cooling for EGR cooler leak (root cause of sensor fouling)
- On M271, check intake manifold flap actuator
- Replace MAP sensor if cleaning doesn't restore signal
- Test-drive and confirm boost tracks correctly
The common misdiagnosis to avoid
Don't approve a Mercedes-quoted 'turbo and intake decontamination' (£900+) on OM651 — clean the sensor, fix the EGR cooler leak that contaminated it, and the code's gone for £200–£300.
Mercedes-Benz P0106 repair cost in the UK
Expect £140–£480 including parts and labour at an independent garage. Main-dealer quotes on Mercedes-Benz are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.
Bob's workshop tip
If you've got an OM651 with both P0106 and slowly disappearing coolant, the EGR cooler is leaking — fix that first, replace the contaminated sensor afterwards. Doing it in the wrong order means a new sensor fouls within weeks.
Codes usually seen alongside P0106 on Mercedes-Benz
- P0299
- P2002
- P0401
Symptoms drivers report with P0106
- Sudden loss of power on a motorway slip road — car drops into limp mode at exactly the point you plant the throttle
- Full power returns after a key-off / key-on cycle, then disappears again 10–20 miles later
- Whistling, hissing or a chuff-chuff noise from the engine bay under acceleration
- Slight oil mist around intercooler pipework or a stain on the underside of the bonnet
- MPG drops 4–8 mpg within a tankful, sometimes with faint black smoke on hard acceleration
- Sometimes paired with P0299 (underboost), P0234 (overboost), or P0401 (EGR flow)
Repairs that clear P0106
- Clean or replace MAP sensor
- Smoke-test intake and boost pipes
- Check EGR isn't stuck open
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0106 guide.
Reading P0106 on a Mercedes-Benz properly
A generic reader will show P0106 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the Mercedes-Benz has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.
Clearing P0106 without fixing it
Erasing the code resets the Mercedes-Benz's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.
Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0106 is showing on your Mercedes-Benz, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.