Powertrain, generic (extended)

P2634 Fuel Pump B Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2634 indicates that the drive of the second fuel pump reads as shorted to battery voltage or carries too much current. For the 6.6 L LML with dual tanks, GM's 2014 table judges the transfer pump relay output while it is switched on and treats 0.5 ohm or less toward controller power, lasting 3 s, as a Type B fault. GM's 2020 diesel table checks the transfer pump driver while it is off instead and logs a Type C code after 20 of 25 samples; it notes that the open-circuit code P2632 may appear alongside. VW uses an overcurrent limit of 1.0 A for the in-line pump on 2014 Golf/GTI and Beetle. A pump with worn brushes or a shorted relay coil can cause it as well as damaged wiring. The open and low faults are P2632 and P2633.

Likely causes

Control wire shorted to a battery-voltage feed
Worn or binding pump drawing excess current
Relay with shorted coil or stuck contacts

Symptoms

  • Second pump runs constantly or is shut off by the module
  • Fuel level display between tanks inconsistent
  • Warning lamp depending on manufacturer

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel pump bwiring harness

Related codes

P2632P2633P2636P0629

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.