01 Why Does Your Transmission Stop Working When It Gets Hot? • 02 Master Your Automatic: A Guide to Using D, D1, D2, D3 Gear … • 03 What Makes Ferrari, Lamborghini and Porsche Sport Cars Uniq… • 04 Don’t Panic: Understanding Power Steering Fluid Leaks (Caus… • 05 10 Lathe Machine Processes That Every Manufacturer Should K… • 06 Your ultimate checklist for buying a used car with confiden… • 07 ECU Tuning Explained: Understanding Stages, Benefits, and P… • 08 From Manifold to Tailpipe: How Exhaust System Components Bo… • 09 Beyond Looks: The Hidden Advantages of Holes on Brake Discs • 10 This Is Why Your Car’s CV Axle Is Failing •

DTC codes / P26xx · Computer and output circuits / P2632

P2632Fuel Pump 'B' Control Circuit /Open

P2632 indicates that the powertrain control module (PCM) has detected an open circuit on the control circuit for fuel pump 'B', which is a secondary or auxiliary fuel pump used in some vehicles to supply fuel under high demand. The PCM commands the pump on and monitors the circuit for expected voltage or current feedback; when the feedback is missing, it sets this code.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaComputer and output circuits

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Engine may stumble or hesitate under heavy load or at high speed if the secondary pump is needed
  • Possible hard starting or extended cranking in conditions requiring the auxiliary pump
  • Reduced engine power or limp mode in some applications
  • Fuel pump 'B' may not run at all, leading to fuel starvation in high-demand situations
  • In rare cases, the engine may stall if the primary pump cannot meet demand alone

Common causes, most likely first

  1. Open or damaged wiring in the fuel pump 'B' control circuit, such as a broken wire or corroded connector
  2. Failed fuel pump 'B' control module or relay
  3. Defective fuel pump 'B' itself, causing an open circuit internally
  4. Loose or disconnected electrical connector at the fuel pump 'B' or control module
  5. Corrosion or water intrusion in the wiring harness or connectors
  6. Faulty powertrain control module (PCM) driver for the fuel pump 'B' circuit, though this is less common

How to diagnose and fix it

  1. Inspect the fuel pump 'B' fuse and replace if blown, as this is the simplest and cheapest first step
  2. Visually inspect the wiring harness and connectors at the fuel pump 'B' and control module for damage, corrosion, or looseness
  3. Disconnect the fuel pump 'B' connector and check for battery voltage on the control circuit when the pump is commanded on; if voltage is present, the pump is likely faulty
  4. Test the fuel pump 'B' control module or relay by swapping with a known-good unit or performing a function test
  5. Perform a voltage drop test on the ground and power circuits to identify excessive resistance
  6. Check for continuity and short-to-ground on the control circuit between the PCM and the pump or module
  7. If all electrical checks pass, suspect the PCM and perform a thorough diagnostic before replacement

Don't overlook the secondary pump circuit

  • Many vehicles use a secondary fuel pump only under specific conditions, so a failure may not produce drivability symptoms until the engine is under heavy load or at high speed.
  • A common misdiagnosis is replacing the primary fuel pump when the fault actually lies in the secondary pump circuit, so always verify which pump is controlled by circuit 'B'.
  • Corroded connectors at the fuel pump module are a frequent cause of open circuits, especially in areas with road salt or high humidity.
  • The PCM may set this code if the control circuit is open even momentarily, so intermittent faults can be challenging to reproduce and may require wiggle testing of the harness.
  • Some vehicles use a fuel pump control module that communicates over a data bus; a fault in that module can set P2632 even if the pump itself is good.

Can I keep driving with P2632?

You can generally drive with this code if the engine runs normally, but avoid heavy loads, towing, or aggressive acceleration because the secondary pump may be needed and its failure could cause fuel starvation. If you notice hesitation, stumbling, or stalling, have the vehicle inspected promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage