P2633 code meaning
Fuel Pump B Control Circuit Low
Powertrain system Generic code P26xx codes Check engine light
What P2633 means
P2633 is the ground-short code of the second fuel pump circuit. GM's 2014 LML diesel table checks the ground-switched relay output of the fuel transfer pump while it is off and flags 0.5 ohm or less between signal and ground, held for 3 s, as Type B. The 2020 diesel table 20OBDG04 looks at the supply-side switch of the rear-tank transfer pump while it is on and stores a Type C code, without warning lamp, after 20 failures in 25 samples of 250 ms. VW's 2014 data books for Golf, GTI and Beetle set P2633 for the auxiliary in-line pump once the signal voltage stays under 2.0 V. GM bulletin PIT5212B groups it with P2632, P2634 and P2636 on 2013 dual-tank chassis cabs. A grounded wire usually blows a fuse or stops the pump.
P2633 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2633
- Blown fuse, second pump does not run
- Fuel not transferred from the auxiliary tank
- Warning lamp depending on manufacturer
Common causes of P2633
- Most likelyChafed pump wire grounded against frame or tank strap
- PossibleShorted pump motor windings
- Less likelyWater in the connector under the vehicle
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel pump bWiring harness
What each part of P2633 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| 33 | The exact fault in that area. |
What to do next
- Note P2633 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2633
What does P2633 mean?
P2633 means "Fuel Pump B Control Circuit Low". P2633 is the ground-short code of the second fuel pump circuit. It is a generic code, so it means the same on every make.
Is it safe to drive with P2633?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2633 fail an emissions test?
Yes, it can. P2633 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2633 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P2633 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.