P2632: Fuel Pump B Control Circuit/Open

Fuel pump B is a second pump beside the main one: a transfer pump between two tanks, an in-line booster or a second in-tank pump. P2632 reports an open in its control circuit. On the 6.6 L LML Duramax with dual tanks, GM's 2014 table 14OBDG10 drives the transfer pump relay through a low-side driver and sets the code as Type B after 3 s above 200 kOhm. In the 2020 diesel table 20OBDG04 it is a Type C code without MIL after 20 of 25 samples. Bulletin PIT5212B on 2013 Silverado/Sierra 3500 chassis cabs asks for a scan tool update before diagnosis. VW sets it below 0.8 mA for the in-line pump of 2014 Golf and Beetle; Ford's 2020-2023 summary uses P2632 for driver feedback faults of pump module B.

Symptoms

• Fuel from the second tank is not transferred, gauge drops faster
• Possible stalling when the main tank runs dry
• Warning lamp depending on manufacturer

Most likely causes

• Failed transfer pump relay, fuse or relay socket
• Open wire or corroded connector at the pump or tank
• Pump motor or pump driver module open internally
• Outdated scan tool cannot command the pump (GM PIT5212B)

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the pump's fuse, relay, and connector
2. Check the continuity of the wire between the component and the control module.
3. Replace the filter if it is due for maintenance
4. Compare commanded and actual pressure in live data
5. Measure the pressure with a suitable gauge
6. Check the sensor and regulator before replacing the pump

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P2632 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 6: Control modules and outputs
• 32: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2632?

Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.

What causes code P2632?

The most common causes are: failed transfer pump relay, fuse or relay socket; open wire or corroded connector at the pump or tank; pump motor or pump driver module open internally.

Related codes

• P2633Fuel Pump B Control Circuit Low
• P2634Fuel Pump B Control Circuit High
• P2636Fuel Pump B Low Flow/Performance
• P0230Fuel Pump Primary Circuit
• P0627Fuel Pump A Control Circuit/Open

Sources

• gsi.ext.gm.com: 14OBDG10 Engine Diagnostics
• gsi.ext.gm.com: 20OBDG04 Diagnostics
• static.nhtsa.gov: MC 10113171 9999
• static.nhtsa.gov: MC 10073689 2280

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.