0261520472
BOSCH 0261520472 High Pressure Fuel Pump for Mercedes M274 2.0T
A2740700501, A2740700401, A2740700101, A2740700001Integrated Solenoid Quantity Control Valve (Y94)-200 barProduct Overview
The Bosch 0261520472 (Mercedes-Benz OE A2740700501 / A2740700401) is the benchmark HDP-5 mechanical high-pressure fuel pump for Mercedes-Benz M274 (longitudinal) and M270 (transverse) 1.6T and 2.0T BlueDIRECT turbocharged engines. Driven by the exhaust camshaft dual-lobe via a roller tappet, this compact radial pump compresses in-tank supply fuel up to 200 bar (2900 psi). Fitted to iconic luxury platforms including the C300, E300, GLC300, and CLA250, it incorporates an integrated solenoid volume control valve (Y94) managed by the ME-SFI engine control unit. Worn units exhibit extended cold start cranking, sudden engine limp mode under acceleration, and check engine warnings with codes P008700 and P008800.
COLD EXTENDED CRANK & PLUNGER SEAL WARNING: A primary symptom of a failing M274 high-pressure pump is an extended cold-start crank (5 to 8 seconds before the engine fires). Internal check valve failure allows rail pressure to bleed down to 0 bar overnight. In severe failures, high-pressure fuel bypasses the internal plunger seal and leaks into the camshaft case, severely contaminating engine oil with gasoline and setting DTC P008700 (fuel pressure too low) or P008800 (fuel pressure too high).
Vehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Mercedes-Benz C-Class W205 (C200 / C300) | Mercedes-Benz M270 / M274 (1.6L & 2.0L BlueDIRECT Turbo) | 2014-2020 |
| Mercedes-Benz E-Class W213 (E200 / E300) | Mercedes-Benz M270 / M274 (1.6L & 2.0L BlueDIRECT Turbo) | 2016-2020 |
| Mercedes-Benz GLC-Class X253 (GLC260 / GLC300) | Mercedes-Benz M270 / M274 (1.6L & 2.0L BlueDIRECT Turbo) | 2015-2020 |
| Mercedes-Benz CLA-Class C117 (CLA250) | Mercedes-Benz M270 / M274 (1.6L & 2.0L BlueDIRECT Turbo) | 2013-2019 |
Technical Specifications
| Specification | Value |
|---|---|
| Pump Generation | Bosch HDP-5 Compact Single-Piston High Pressure Pump |
| Operating Rail PressureCore Spec | |
| Cam Drive Type | Exhaust Camshaft Dual Lobe via Roller Tappet |
| Roller Tappet Part Number | Mercedes-Benz OE A2740500106 |
| Integrated Component | Solenoid Quantity Control Valve (Y94) |
| Flange Fastener Torque | 10 N·m (Torx M6, alternating two-step torque) |
| High Pressure Output Line Nut Torque | 28 N·m (Counter-hold body adapter) |
| Tightening Torque | 28 N·m |
| Hold Down Torque | 10 N·m |
| Default Safety Pressure Mode | Mechanical bypass ~5 bar in unpowered state |
| Operating PressureCore Spec |
Matched High-Pressure Fuel Pump (Fuel Circuit Assembly)
Operates on the same high-pressure rail circuit. When troubleshooting low rail pressure (DTC P0087), verify pump volumetric delivery before replacing injectors.
Installation Tips
Tools needed: E-Torx sockets (E8 and E10) and 17mm line flare wrench, Torque wrench calibrated for 10-28 N·m, Clean engine oil for pump O-ring and roller tappet lubrication, Shop rags and eye protection for high-pressure fuel bleed-off, XENTRY or advanced diagnostic scanner for fuel rail pressure adaptation reset
- Disconnect the vehicle 12V battery and allow the engine to cool completely.
- Wrap the high-pressure fuel line union in lint-free shop towels and slowly loosen the 17mm flare nut to vent residual 200-bar rail pressure.
- Disconnect the electrical connector from the Y94 quantity control valve on top of the pump.
- Disconnect the low-pressure fuel feed hose spring clamp and remove the hose.
- Evenly loosen the two E-Torx pump mounting bolts half a turn at a time to relieve internal plunger spring pressure.
- Remove the pump from the cylinder head. Extract roller tappet A2740500106 and inspect for surface pitting, flat spots, or axial play; replace if worn.
- Clean the cylinder head mounting surface and apply clean engine oil to the new pump Viton O-ring.
- Position the camshaft at base circle (lowest lobe lift) so the pump mounts without cocking against cam pressure.
- Insert the roller tappet into the bore with engine oil, position the pump, and tighten mounting bolts finger-tight.
- Torque the two mounting bolts alternately in two stages to 10 N·m.
- Thread the high-pressure steel pipe flare nut by hand; counter-hold the pump body fitting with an open-end wrench and torque flare nut to 28 N·m.
- Reconnect low-pressure fuel hose and electrical harness; cycle ignition to prime system and verify zero fuel leaks.
- Counter-Holding Hex Fitting Mandate: When tightening the 17mm steel high-pressure pipe flare nut to 28 N·m, you MUST counter-hold the pump body adapter with a 19mm open-end wrench. Torquing without counter-holding loosens the internal threaded joint and creates fire hazards.
- Camshaft Position Verification: Never force the pump mounting bolts down when the camshaft lobe is at peak lift. Rotating the engine so the cam lobe is on its base circle ensures effortless, straight bolt engagement and prevents stripped aluminum threads.
- XENTRY Adaptation Reset Recommendation: After replacing the HPFP on M274 engines, use XENTRY or a professional scan tool to perform 'Reset adaptations of high-pressure fuel circuit' so the ECM relearns the new pump volumetric displacement immediately.
Frequently Asked Questions
What causes an extended crank of 5 to 8 seconds on Mercedes C300 or E300 M274?
On Mercedes M274 engines, an extended cold start is the classic signature of a failing Bosch 0261520472 HPFP. The internal high-pressure non-return valve fails to seal, causing fuel rail pressure to bleed off from 50 bar to 0 bar overnight. During cranking, the engine must crank until the mechanical pump rebuilds start pressure.
What diagnostic trouble codes are stored when the M274 high pressure pump fails?
The primary fault codes stored in the ME-SFI control unit are P008700 (The fuel pressure in the system is too low) and P008800 (The fuel pressure in the system is too high). In severe cases of cam follower wear, cam correlation code P001600 may also accompany fuel delivery faults.
Can a failing 0261520472 pump cause raw fuel smell in the engine oil?
Yes. When the pump internal piston shaft seal degrades, high-pressure fuel is forced past the seal into the cylinder head camshaft chamber. The fuel mixes with engine oil, diluting the 229.5 lubricant and triggering strong gasoline odor on the dipstick.
Should I replace the roller tappet when replacing the HPFP on Mercedes M274?
Yes. Standard Mercedes repair practice requires replacing the roller tappet (OE A2740500106) along with the pump. A worn roller creates excess clearance and abnormal impact forces that rapidly destroy the new pump internal piston.
Say this to the shop: How do I test the HPFP before replacing expensive low-pressure modules?
Ask the technician: 'Please hook up a diagnostic tool, shut the engine off, and observe actual high-pressure rail pressure decay over 10 minutes. If pressure drops immediately to 0 bar and low-pressure supply maintains 6.0 bar during cold crank, the HPFP check valve is definitively failed.'
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
Injector Circuit Malfunction / Open Circuit
Solenoid coil resistance drift (0.2-0.5 Ω) or piezo stack degradation triggers driver stage shutdown on affected cylinders.
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
Cross-Reference & Compatibility
Sister parts, same-platform variants, and known incompatibilities.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.