P2636

Code

LAND ROVER P — Powertrain

Low flow / performance fuel pump B

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 18 EN: 48 RU: 34

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Page language: EN

Causes

Failed or weak secondary/in-tank fuel pump (pump B)
Blocked or restricted fuel supply (filter, pickup, lines)
Faulty fuel pump driver module or relay
Low supply voltage or poor ground to pump
Wiring harness damage, corrosion or connector fault to pump B
Faulty fuel pressure sensor or incorrect sensor signal

Symptoms

Engine hesitation, stalling or reduced power under load
Hard starting or no-start condition in some cases
Check Engine Light (MIL) illuminated with P2636 stored
Poor acceleration or limp-home mode
Fuel pressure lower than specification, especially under demand

What to check

Scan for freeze frame and related DTCs; record fuel pressure, pump current and voltage live data
Visually inspect fuel pump connectors, wiring, fuse and relay for damage or corrosion
Check battery voltage and starter/charging system health (adequate supply to pump)
Inspect fuel filter and inlet strainer for blockage
Measure fuel rail/static and dynamic pressure with a gauge at idle and under load
Back-probe pump power and ground while commanding pump on; measure voltage and current draw

Signal parameters

Fuel rail pressure (kPa or bar) — should meet manufacturer spec at idle and under load
Fuel pump supply voltage (V) at pump connector when commanded — ~battery voltage (12–14V)
Fuel pump current draw (A) — compare to known good spec or similar pump
Pump duty cycle or command signal (%) from ECM to fuel pump driver (if applicable)
Fuel pressure sensor voltage (V) or PID vs commanded pressure
Short-term and long-term fuel trims (%) — large positive trims may indicate low fuel delivery

Diagnostic algorithm

Read and record all stored codes and freeze-frame data. Note engine load, RPM and fuel pressure at time of fault.
Visually inspect wiring, connectors, fuses and relays related to fuel pump B. Repair any damage or corrosion.
Verify battery condition and supply voltage to pump while cranking and running.
Back-probe pump power and ground; command pump on via scan tool and confirm voltage at pump. If no voltage, check relay/driver and control signal from ECM.
Measure pump current draw. Compare to specification or a known-good pump. Excessive or low current indicates mechanical or electrical failure.
Perform static and dynamic fuel pressure tests at the fuel rail: check idle pressure and pressure while applying load (accelerator or road test). Note pressure drop under demand.
Inspect/replace fuel filter and sump strainer if contaminated or restricted.
If wiring, relay and supply are good but flow/pressure remain low, remove and bench-test pump B or replace pump assembly. Follow vehicle-specific procedures for in-tank pump removal and fuel system safety.
Verify fuel pressure sensor accuracy by comparing sensor PID to measured gauge pressure. Replace sensor if out of tolerance.
After repairs, clear codes and road test under the conditions that previously set the code. Re-scan to confirm fault does not return.

Likely causes

In-tank pump B worn bearings or impeller reducing flow
Clogged fuel filter or sump strainer restricting intake to pump B
Open/short or high-resistance connection in pump B power/ground circuit
Failed fuel pump relay or pump driver module not supplying correct current
Fuel pressure sensor reporting lower-than-actual pressure (false low)
Collapsed fuel line under vacuum or kinked hose reducing flow

Fault status

⚠️ Status

Fuel pump B flow/performance below expected. ECM detected insufficient fuel delivery from pump B.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5 - 3.0 hours

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P2636 — Low flow / performance fuel pump B