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P1259 Code: How to Diagnose and Fix the Code! 

  • Cars Explained
  • Gerard Stevens
  • 6 minutes

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Imagine you’re enjoying driving in your Honda car, and suddenly the check engine light turns on. It can create so much tension in you. In addition, the check engine light can turn on for various OBD II codes. So, while checking, you find that your car has activated a P1259 code. 

It is one of the frequent error codes that shows up in a Honda car. P1259 code indicates VTEC System Malfunction. It is a manufacturer-specific error code, implying it does not apply to all cars. It only affects certain automobile brands, such as Honda and Acura. The definition, diagnosis, and repair specifications differ from one make and model to the next. 

So, what is the P1259 code? What are the causes and symptoms? How can you fix it, and how much will that cost? Know in detail about this Diagnostic Trouble Code (DTC) via our blog! 

What does code P1259 mean? 

P1259 is an OBD-II code that indicates a manufacturer-specific code known as VTEC (Variable Valve Timing and Lift Electronic Control) System Circuit Fault as established by Honda (Bank 1). 

The error code indicates a problem, fault, or failure in the electrical control/monitoring system of the VTEC mechanism on Bank 1, as detected by a signal from the PCM (Powertrain Control Module). On V-type engines, Bank 1 refers to the cylinder bank that comprises cylinder number 1. 

The VTEC technology by Honda controls the elevator and the duration of the engine valves. This system employs two or three camshaft lobe profiles that can be hydraulically changed to increase the engine’s volumetric efficiency. If the P1259 code appears at 4000 RPM or below, it’s typically a problem with the VTEC pressure switch wiring or a broken switch. It’ll almost always be an oil issue if the code appears at 4000 RPM or higher. 

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What are the causes of the P1259 code? 

The P1259 error code implies an electrical problem with the VTEC control system. Therefore, all diagnostic methods for this code should start with a visual examination of all connected wiring and connectors. These are some of the common causes of code P1259. 

  • The VTEC solenoid is defective 
  • Possibility of a broken VTEC oil pressure switch 
  • Damage to VTEC solenoid cables or connectors could result in an open or short circuit 
  • The engine oil level or pressure may be lower than what’s required 
  • Presence of dirty, degraded, or unsuitable engine oil 
  • Failure of PCM. Since this is an uncommon cause, you need to seek the fault somewhere else before replacing any control module 

What are the symptoms of the P1259 code? 


P1259 code is usually accompanied by a few symptoms. Here are some of the most common symptoms when this DTC code activates. 

  • A check engine light called the Malfunction Indicator Lamp (MIL) will turn on when the car is running. 
  • The car will have reduced power in VTEC mode but will have normal power in non-VTEC mode. 
  • Lower ratios are sluggish and hesitant to downshift when accelerating in VTEC mode. 
  • You may hear knocking or rattling sounds coming from the engine’s top. 
  • You may hear whistling while driving at a stoplight. 

When examined with a scan tool connected via an OBD-II port or when moving all electrical components involved with the VTEC system to see if each one works properly, it’s very uncommon for there to be no visible indications. 

How serious is the P1259 code? 

A P1259 code is not a serious issue that will cause major problems to your car. However, the code can cause considerable harm to other vital components if you don’t fix it even after a long period. 

Can I drive with a P1259 code? 

Yes. Driving the car with the code is safe, but you should check the engine oil to ensure it isn’t low and causing the problem. 

How to diagnose P1259 code 

A technician will do the following to diagnose the error code. 

  • On Bank 1, perform a VTEC Cylinder Balance test to ensure that all cylinders generate power. 
  • Check for 12 volts at the solenoid’s connector while turning on the ignition switch to confirm it is working properly (RUN). 
  • Check for any issues with the engine’s oil pressure. Perform additional diagnostics on the vehicle if there is no or low oil pressure. 
  • On V-type engines, inspect and clean up all electrical connections in the circuit if everything else checks out fine and if there is good power production from each bank. 
  • When the ignition switch is in the ON (RUN) position, check for any hissing noises and look for shorts in VTEC Control Solenoid Valve A and B circuits. 
  • Replace the VTEC solenoid if everything else appears in order and there are no oil pressure or electrical issues. 

Common mistakes that happen while diagnosing the code 

These mistakes can happen when diagnosing the P1259 code. 

  • You should initiate a proper diagnosis to identify some visible symptoms so that the cause of the problem can be identified and corrected. 
  • This trouble code is frequently confused with Bank 2 or Bank 3 when doing a VTEC test for Bank 1 to determine where the issue is located inside the system. 

How to fix the P1259 code 

You can follow these steps to fix the error code. 

  • Low oil pressure is the most common cause of error code P1259 or VTEC system failure. As a result, if your oil is due for servicing, make sure you check it. If necessary, change the oil and filter. Clear the codes before giving them a shot. 
  • The VTEC oil pressure switch, located just above the oil filter, is the next possible cause. Replace it with a genuine Honda oil pressure switch if the oil pressure switch is damaged. 
  • Do a visual inspection of the VTEC system solenoid electrical circuit’s wires, connectors, and other components. Conduct essential repairs and adjustments if you see wear and tear or friction damage. 
  • Replace the components if you find any defects during these examinations. 

How much does it cost to fix the P1259 code? 

The cost of repairing a P1259 code depends on the kind of repair you need. For instance, the VTEC solenoid costs around $300-$500 to replace, diagnostics costs $100-$200, and labor costs $100-$150. 

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