Skip the auto shop - Our mechanics make house calls

P2633 OBD-II Trouble Code: Fuel Pump B Control Circuit Low

check engine light

P2633 code definition

The P2633 trouble code detects a problem with the fuel pump B control circuit.

What the P2633 code means

The P2633 code is a generic OBD-II trouble code. This code notes an issue with the fuel pump B control circuit, with the “B” referencing an of the control circuit. When the powertrain control module (PCM), or any number of other control modules (such as the antilock brake control module, fuel injection control module, or instrument panel control module) notices a fault in the fuel pump B control circuit, the P2633 code will be triggered.

What causes the P2633 code?

There are a few common causes for the P2633 code, including:

  • Malfunctioning fuel pump
  • Faulty fuel pump relay
  • Malfunctioning controller area network (CAN) bus
  • Shorted or corroded wires, or open connectors in the CAN bus harness
  • Broken ground wire
  • Loose or broken control module ground strap
  • In rare cases, a faulty PCM or other control module

What are the symptoms of the P2633 code?

The P2633 trouble code will usually be accompanied by an illuminated Check Engine Light. The vehicle may also illuminate the fuel cap malfunction warning light. There are unlikely to be any drivability issues with the P2633 code.

How does a mechanic diagnose the P2633 code?

The P2633 code will be diagnosed using a normal OBD-II trouble code scanner. A certified mechanic will look at the freeze frame data for the P2633 code to assess the issue, and to look for any additional trouble codes that may be detected. Next, the technician will reset the trouble codes and restart the vehicle to see if the code persists. If the code does not return, it was likely triggered erroneously.

If the P2633 trouble code is still detected after the restart, the technician will have to begin inspection of the CAN bus and the fuel pump. The mechanic will start with the wires, connectors, and ground straps, because they offer the easiest and most cost-effective repair. If no issues are noted there, the technician will move to the CAN bus and the fuel pump. It is best for the technician to use a CAN scanner when inspecting the CAN bus.

When any component is replaced, the technician will reset the trouble codes and restart the vehicle again, before continuing with further inspection.

Common mistakes when diagnosing the P2633 code

The most common issue when diagnosing the P2633 code comes from a failure to follow the basic trouble code diagnosis protocol. All steps of the protocol should be followed in order to ensure that the mechanic not only finds and resolves the issue, but does so in the timeliest and most cost-effective manner possible.

Failure to follow the standard diagnosis protocol can result in replacing the fuel pumps or fuel pump relays when the issue was with the communication from the CAN bus.

How serious is the P2633 code?

The P2633 trouble code will not keep a vehicle from operating and being drivable. However, the code should still be addressed and the issue resolved as soon as the P2633 code is detected.

What repairs can fix the P2633 code?

Some of the most common fixes for the P2633 trouble code include:

Additional comments for consideration regarding the P2633 code

Failure to use a CAN scanner when inspecting the P2633 code may result in the need to disconnect and inspect each pin of the CAN bus manually, which is a very time intensive endeavor.

Need help with a P2633 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...


Related questions

Q: Check Engine light comes on when cars RPMS go over 4000 error code P0344

Hi there. This code is for a bad camshaft sensor. It can be caused by a bad sensor or it can come from another issue. I usually check the sensor first and then I check the timing belt. Most of...

Q: Check Engine light coming on

It's possible that your coolant is leaking or the sensor was faulty out of the box. I would recommend having a certified mechanic diagnose your overheating issue, and verify that there are no other leaks or problems.

Q: What exactly does the code P3fff mean?

Hi there. The code P3fff means that there is an issue with the PCM (the computer to the vehicle). The codes regarding gas recirculation flow and mass air flow are coming on either due to the PCM failure or due...