P3400 OBD-II Trouble Code: Cylinder Deactivation System Bank 1

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Cost of diagnosing the P3400 code

P3400 is a diagnostic trouble code (DTC) for "Cylinder Deactivation System Bank 1". 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
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Toyota$70.00$30.00
BMW$70.00$30.00
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P3400 trouble code definition

The P3400 diagnostic trouble code indicates that there is a performance issue with the Cylinder Deactivation System in Bank 1.

Related Trouble Codes:

P3401 OBD-II Trouble Code: Cylinder 1 Deactivation/Intake Valve Control Circuit/Open P3402 OBD-II Trouble Code: Cylinder 1 Deactivation/Intake Valve Control Performance P3403 OBD-II Trouble Code: Cylinder 1 Deactivation/Intake Valve Control Circuit Low P3404 OBD-II Trouble Code: Cylinder 1 Deactivation/Intake Valve Control Circuit High

P3409 OBD-II Trouble Code: Cylinder 2 Deactivation/Intake Valve Control Circuit/Open P3410 OBD-II Trouble Code: Cylinder 2 Deactivation/Intake Valve Control Performance P3411 OBD-II Trouble Code: Cylinder 2 Deactivation/Intake Valve Control Circuit Low P3412 OBD-II Trouble Code: Cylinder 2 Deactivation/Intake Valve Control Circuit High

P3417 OBD-II Trouble Code: Cylinder 3 Deactivation/Intake Valve Control Circuit/Open P3418 OBD-II Trouble Code: Cylinder 3 Deactivation/Intake Valve Control Performance P3419 OBD-II Trouble Code: Cylinder 3 Deactivation/Intake Valve Control Circuit Low P3420 OBD-II Trouble Code: Cylinder 3 Deactivation/Intake Valve Control Circuit High

P3425 OBD-II Trouble Code: Cylinder 4 Deactivation/Intake Valve Control Circuit/Open P3426 OBD-II Trouble Code: Cylinder 4 Deactivation/Intake Valve Control Performance P3427 OBD-II Trouble Code: Cylinder 4 Deactivation/Intake Valve Control Circuit Low P3428 OBD-II Trouble Code: Cylinder 4 Deactivation/Intake Valve Control Circuit High

P3433 OBD-II Trouble Code: Cylinder 5 Deactivation/Intake Valve Control Circuit/Open P3434 OBD-II Trouble Code: Cylinder 5 Deactivation/Intake Valve Control Performance P3435 OBD-II Trouble Code: Cylinder 5 Deactivation/Intake Valve Control Circuit Low P3436 OBD-II Trouble Code: Cylinder 5 Deactivation/Intake Valve Control Circuit High

P3441 OBD-II Trouble Code: Cylinder 6 Deactivation/Intake Valve Control Circuit/Open P3442 OBD-II Trouble Code: Cylinder 6 Deactivation/Intake Valve Control Performance P3443 OBD-II Trouble Code: Cylinder 6 Deactivation/Intake Valve Control Circuit Low P3444 OBD-II Trouble Code: Cylinder 6 Deactivation/Intake Valve Control Circuit High

P3449 OBD-II Trouble Code: Cylinder 7 Deactivation/Intake Valve Control Circuit/Open P3450 OBD-II Trouble Code: Cylinder 7 Deactivation/Intake Valve Control Performance P3451 OBD-II Trouble Code: Cylinder 7 Deactivation/Intake Valve Control Circuit Low P3452 OBD-II Trouble Code: Cylinder 7 Deactivation/Intake Valve Control Circuit High

P3457 OBD-II Trouble Code: Cylinder 8 Deactivation/Intake Valve Control Circuit/Open P3458 OBD-II Trouble Code: Cylinder 8 Deactivation/Intake Valve Control Performance P3459 OBD-II Trouble Code: Cylinder 8 Deactivation/Intake Valve Control Circuit Low P3460 OBD-II Trouble Code: Cylinder 8 Deactivation/Intake Valve Control Circuit High

What the P3400 code means

When starting or idling, and when the vehicle is operating under heavy loads, the engine will operate in V8 mode, using 8 cylinders. However, when driving conditions are light the engine will deactivate 4 of the 8 cylinders to change from V8 mode to V4 mode.

The powertrain control module (PCM) will determine what the vehicle driving conditions are using information it receives from the mass airflow (MAF) sensor, the intake control manifold absolute pressure (MAP) sensor, and the throttle position (TP) sensor.

The PCM will then instruct the cylinder deactivation solenoids to begin the cylinder deactivation process. The cylinder deactivation solenoids will deactivate cylinder 1, cylinder 4, cylinder 6, and cylinder 7, by restricting the flow of oil to the valve lifters for these cylinders, and preventing the intake valves and exhaust valves from opening. The vehicle cannot operate under V4 mode if these 3 sensors are not within the correct range.

When the PCM detects that the measured values of the mass airflow sensor, the throttle position sensor, and the intake control manifold absolute pressure sensor, are not within the predetermined range for V4 mode it will store the P3400 diagnostic trouble code.

What causes the P3400 code?

  • Defective cylinder deactivation solenoid
  • An open or short in the cylinder deactivation solenoid harness
  • A bad electrical connection in the cylinder deactivation solenoid circuit
  • Defective mass airflow sensor
  • Defective throttle position sensor
  • Defective intake control manifold absolute pressure sensor
  • Defective lifters
  • Restricted oil passages
  • Low engine oil level
  • Poor oil pressure on the lifters

What are the symptoms of the P3400 code?

  • Check Engine Light is on
  • Engine is vibrating

How does a mechanic diagnose the P3400 code?

  • Make sure engine oil levels are correct. Also make sure that the engine oil pressure is correct.

  • Use the OBD-II scanner to collect all of the diagnostic trouble codes that have been stored by the powertrain control module (PCM).

  • If the powertrain control module (PCM) has stored other deactivation and/or oil pressure diagnostic trouble codes, these should be diagnosed first.

  • Use the OBD-II scanner to clear the trouble codes.

  • Test the cylinder deactivation solenoid #1 by actuating it with a scan tool. A solenoid that is working properly will vibrate and make a clicking noise. If the cylinder deactivation solenoid #1 is not working properly, check the oil passages for debris, clean the oil passages if necessary, and replace the solenoid.

  • If the cylinder deactivation solenoid #1 is working properly, the cylinder deactivation solenoid #7 will need to be inspected.

  • Test the cylinder deactivation solenoid #7 by actuating it with a scan tool. A solenoid that is working properly will vibrate and make a clicking noise. If the cylinder deactivation solenoid #7 is not working properly, check the oil passages for debris, clean the oil passages if necessary, and replace the solenoid.

  • If the cylinder deactivation solenoid #7 is working properly, inspect the oil passages to the lifter.

  • Clean restricted oil passages, as necessary. The engine block may need to be disassembled of the entire engine is restricted.

  • Replace the lifters if the oil passages are not restricted.

Common mistakes when diagnosing the P3400 code

The most common mistake when diagnosing this code is neglecting to check the oil passageways for dirt and sludge. Clogged oil passageways will reduce engine oil pressure and will prevent the cylinder deactivation solenoids and lifters from operating properly when switching from V4 mode to V8 mode.

Be sure to check the oil passageways thoroughly so that money does not have to be spent on unnecessary parts and repairs.

How serious is the P3400 code?

  • When this code is present, the car will operate on all 8 cylinders instead of 4 cylinders.

  • This will cause a loss of fuel economy, and increase engine emissions.

  • Although the P3400 diagnostic trouble code is not generally considered a serious one, it is important not to allow a long period of time to pass before having it diagnosed.

What repairs can fix the P3400 code?

  • Replace cylinder deactivation solenoid #1
  • Replace cylinder deactivation solenoid #7
  • Clear cylinder deactivation solenoid oil passages of dirt and debris
  • Clear lifter oil passages of dirt and debris
  • Replace lifters in engine
  • If entire engine is packed with dirt and sludge, is will be necessary to disassemble the entire engine in order to clean it properly.

Additional comments for consideration regarding the P3400 code

This code can become very involved and may need the entire engine disassembled in order to repair the problem correctly. This is a big job, even for the most seasoned technician so it is important not to begin disassembling the engine if you are not sure how to do so properly.

Need help with a P3400 code?

YourMechanic offers certified 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.

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