P2636
Fuel Pump "B" Low Flow / Performance
- Severity
- High
- Driving
- Drive only to a garage
Fuel pump "B" is running but not delivering the flow the module expects. The circuit is not being blamed - this is a measurement of what actually arrives. A blocked filter and a tired pump produce the same reading, and the filter is far cheaper to eliminate.
Possible causes
- CommonBlocked or overdue fuel filter
- CommonWorn fuel pump
- CommonBlocked pickup strainer in the tank
- PossibleRestricted or kinked fuel line
- PossibleLow fuel level, so the pump draws air
- PossibleHigh resistance in the pump supply wiring, so the pump runs slowly
What you might notice
- Loss of power under load, particularly uphill or when overtaking
- Hesitation at higher speeds
- Hard starting
- Cutting out
- Check engine light on
What to check, in order
- Check the fuel filter and when it was last changed. It is by far the cheapest thing here and a very common cause.
- Note when the symptom appears. A fault that only shows under load or at high speed is the classic signature of a supply that cannot keep up.
- Perform a voltage drop test on the pump supply and earth. A pump running on reduced voltage delivers reduced flow while testing as electrically sound.
- Check the fuel pressure against specification, both at idle and under load.
- Avoid running the tank very low. The pump is cooled by the fuel around it, and habitually running near empty shortens its life.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Computer output circuits and control module
P2600P2601P2602P2603P2604P2605P2606P2607P2608P2609P2610P2611P2612P2613P2614P2615P2616P2617P2618P2619P2620P2621P2622P2623P2624P2625P2626P2627P2628P2629P2630P2631P2632P2633P2634P2635P2636P2637P2638P2639P2640P2641P2642P2643P2644P2645P2646P2647P2648P2649P2650P2651P2652P2653P2654P2655P2656P2657P2658P2659P2660P2661P2662P2663P2664P2665P2666P2667P2668P2669P2670P2671