P2771 OBD-II Trouble Code: 4WD Low Switch Circuit

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P2771 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2771 code

P2771 is a diagnostic trouble code (DTC) for "4WD Low Switch Circuit". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P2771 DIAGNOSTIC Get a fair and transparent estimate upfront

check engine light

P2771 code definition

Exhibited on all-wheel or four-wheel-drive vehicles only, a P2771 trouble code signifies a fault with the four-wheel-drive low switch circuit. Subsequently, the Powertrain Control Module (PCM) stores the trouble code and illuminates the Check Engine light. Associated codes include P2772, P2773, and P2774.

What the P2771 code means

The four-wheel-drive switch actuates the changing of gears ratios in the four-wheel-drive system. When PCM detects an abnormal reading in the transfer case control system, which contains the four-wheel-drive low switch circuit, a P2771 trouble code is sent to the PCM and the Check Engine light illuminates.

What causes the P2771 code?

The causes of a P2771 trouble code ranges from faulty solenoids, sensors, and switches to defective wiring and connectors. A malfunctioning four-wheel-drive switch or actuator can also cause the storage of this code.

What are the symptoms of the P2771 code?

While the storing of a P2771 trouble code might not cause any outward symptoms, it could also result in a total failure by the transfer case. In addition to the illumination of the Check Engine Light, this code can be exhibited through such common symptoms as a failure to shift from two-wheel to four-wheel-drive, engine stalling when stopped, and difficulty in shifting.

How does a mechanic diagnose the P2771 code?

To properly diagnose a P2771 trouble code, the mechanic should have an advanced scanner and a digital volt/ohmmeter. The mechanic should also perform the following steps:

  • Start by checking out all wiring, connectors, and components.

  • Download any stored codes and freeze frame data for later use if needed. The mechanic can do this by connecting the code reader to the diagnostic connector.

  • If, after clearing the code, it immediately returns, check the battery voltage on the input side of the switch to see what the voltage reading is. Use a manufacturer's wiring schematic to find the four-wheel-drive switch.

  • In cases of no voltage, make sure to disconnect any related control modules and check the continuity between the fuse and the input circuit at the clutch position sensor using a digital volt/ohmmeter.

  • If you detect voltage, use the scanner to turn the four-wheel-drive system on, checking for voltage on the output size of the switch. If no voltage is present on the output side of the switch, then the four-wheel-drive switch is most likely at fault.

  • If needed, check circuit continuity and resistance between the switch and the PCM. The mechanic should make sure to disconnect any related control modules to prevent memory loss.

  • Clear the code and test the system to make sure of success and to see if the code returns.

Common mistakes when diagnosing the P2771 code

Mechanics replace or rebuild transfer cases when not needed when a P2771 trouble code is stored in the erroneous assumption this might fix the problem and clear the code. This fix for a P2771 trouble code is extraneous and expensive for vehicle owners.

How serious is the P2771 code?

When suffering from a P2771 trouble code, a vehicle transfer case can suffer a total failure. The vehicle can also have other problems, including shifting from two-wheel to four-wheel-drive and the engine stalling while the vehicle is stopped.

What repairs can fix the P2771 code?

After inspecting and diagnosing a P2771 trouble code, mechanics should make the following repairs as needed:

  • Replace any damaged wiring, connectors, or other components.

  • Replace the four-wheel-drive switch if its proves to be faulty upon testing with the digital volt/ohmmeter.

  • Replace any additional open or shorted circuits and connectors after additional testing.

  • Replace and reprogram the PCM if it is found to be at fault.

Additional comments for consideration regarding the P2771 code

If a P2771 trouble code is stored in a two-wheel-drive vehicle, the mechanic should check the PCM as the problem most likely lies there. In a case such as this, the PCM itself is at fault or is suffering from a programming error.

Need help with a P2771 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.

trouble codes
Check Engine Light
P2771

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P2771 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,696

Rating Summary
3,372
162
42
24
96
3,372
162
42
24
96

Jay

34 years of experience
566 reviews
Jay
34 years of experience
Very professional,
1998 JEEP GRAND CHEROKEE - CHECK ENGINE LIGHT IS ON - GRAND TERRACE, CALIFORNIA

Oscar

21 years of experience
66 reviews
Oscar
21 years of experience
Oscar is awesome he pays attention to the details, very honest, timely and very knowledgable. From here on out he's my go to guy!! First Class!!!
2010 FORD F-250 SUPER DUTY - CHECK ENGINE LIGHT IS ON - WOODBINE, MARYLAND

Breck

17 years of experience
355 reviews
Breck
17 years of experience
Breck was very nice and knowledgeable.
2008 TOYOTA RAV4 - CHECK ENGINE LIGHT IS ON - HOUSTON, TEXAS

Kinder

18 years of experience
40 reviews
Kinder
18 years of experience
Exceeded my expectations... The weather knocked my appointment off track a couple of times, but Kinder's constant updates and timely communication made it a non-issue. He Made it to our rescheduled appointment a little earlier than scheduled ready to go. Before beginning any work he explained the process, confirmed what I wanted done and how it worked. Upon finishing.. he test drove vehicle and explained to me "what" he had done and what was discovered causing the issues. He didn't bash my prior mechanics he just explained that some vehicles need a little more knowledge than others...If my long winded comment is any indication... as I stated earlier, my expectations were exceeded. For those of you, like myself , who totally enjoy your European car but not the sometimes sticker shock of maintenance... i strongly encourage you to try this service and I strongly urge you to request Kinder... You can thank me later. Royce
2007 MERCEDES-BENZ S550 - CHECK ENGINE LIGHT IS ON - MABLETON, GEORGIA

More related articles

Symptoms of a Bad or Failing Flexible Clutch Hose
Common signs include difficulty shifting, low clutch fluid, and feeling no resistance at the clutch pedal.
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...

Related questions

Q: Check Engine Light is on - 2007 Toyota Sienna

This code relates to a heated oxygen sensor which is a unit inside your exhaust system that reads exhaust gases and relays this information to the car's computer. The computer uses this information to make adjustments to fueling. This sensor...

Q: Have already changed plugs, plug wires, and ignition coils, but the engine still wants to stall and shake a lot.

You may need to have you crankshaft position sensor relearned or have the sensor replaced. Also the catalytic converter could be partially clogged. If everything is working properly, then it is possible that some intake bolts could have...

Q: I have a trouble code P0622: Generator Filed Terminal Circuit and my battery light is on.

The generator is the same thing as the alternator. If you are running through batteries, then it's likely that the amount of voltage from the alternator is too much for the battery to take. The other factor may be that...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com