Causes and Fixes of a P1259 Code on a Honda Accord

By | September 24, 2022

Causes and Fixes of a P1259 on a Honda Accord
A Honda Accord with a P1259 code means there could be a problem with the VTEC control system.

The VTEC control system generates more horsepower by varying the oil pressure going to the cams when the engine speeds up, which allows for a larger valve lift.

What is a Honda Accord P1259 Code?

A Honda Accord P1259 Code is a “VTEC System Malfunction”.

The Powertrain Control Module (PCM) monitors oil pressure conditions and notes any disparities. When the PCM command finds fault with the oil conditions downstream and the oil pressure switch, the system is considered at fault and gives out the P1259 error code.
What is a Honda Accord P1259 Code
VTEC was the first commercially successful variable valve timing engine. Over the past thirty years, the engine has been a workhorse for Honda, and the platform remains fundamental to Honda’s product line for years to come. The goal of four-cylinder engines in the 80 was to extract as much horsepower and torque as possible. The VTEC spurred an industry-wide shift to variable valve timing.

Honda Accord P1259 Code Symptoms

  • Engine light on
  • Check the oil On
  • Unstable engine oil pressure

The most common symptoms of a P1259 come the engine or oil light comes on and gives a warning.

Common Causes of a Honda Accord P1259 Code

  • Low or Dirty Oil
  • VTEC Solenoid
  • VTEC Solenoid Harness
  • Wiring Connections in VTEC Circuitry
  • Oil Pressure Switch

3 Common Fixes for a P1259 Code on a Honda Accord

  1. Dirty or Low Oil
  2. Dirty or Low Oil
    If the oil is old and dirty, it can cause a P1259 error code.

    Check the oil if the oil is low or dirty.

  3. Oil Pressure Switch
  4. Honda Accord Oil Pressure Switch
    A faulty oil pressure switch is another common problem with a P1259 code in a Honda Accord.

    The oil pressure switch sends information to the onboard computer (PCM) if the oil pressure is correct.

    If the switch fails, the PCM will not receive the correct information and send out a P1259 code.

  5. Valve Timing Solenoid
  6. Honda Accord Valve Timing Solenoid
    A failing VTEC Solenoid Spool will also cause issues.

    A small filter inside the VTEC often gets clogged and needs to be cleaned, so the oil can pass through again.

    Newer Honda models will have a Variable Timing Solenoid, while older cars will have a VTEC Solenoid Spool.

    Can the Honda Accord Operate with a P1259 Code

    As long as the engine oil is not low or dirty, a P1259 is not a severe problem to the overall operation of the engine. There may be a problem with a vital component, however.

    P1259 is one of the most frequent OBD2 error codes. The OBD2 code refers to the Honda VTEC System Circuit Fault (Bank 1). The scan places the fault directly in the electrical control monitoring system of the VTEC.
    Honda Accord P1259 Code Symptoms
    The VTEC, or Variable Valve Timing and Lift Electronic Control, was developed to produce more efficiency out of a four-cylinder engine for Honda. The VTEC produced more torque in high and low bands and increased the horsepower per liter and throughout the band. It was built in 1984 with specific efficiency targets in mind.
    The original VTEC design replaced the single cam lobe with multi-part rocker arms.

    Using a dual camshaft profile, the PCM can optimize for low-rpm stability and high-rpm performance. Switching of the two cam lobes is controlled by the vehicle’s computer, based on speed and load. The VTEC engine is susceptible to valve timing, duration, and lift.

    Honda continues to evolve the VTEC engine with its moniker, now i-VTEC. The two camshaft profiles are combined with variable valve timing.

    Low oil pressure is usually the cause of a Honda Accord P1259 OBDII fault code.

    A P1259 code points to a problem with the VTEC system.

    Several components can cause the issue, including the oil pressure switch, valve timing solenoid, and low or dirty oil is the most common problem.

    The VTEC delivers an engine that performs well across all power bands at a wider RPM range than most other engines. It can deliver smooth, consistent power with excellent gas mileage in all driving situations.

    When it is working correctly, the VTEC can handle maximum power at all RPMs without losing efficiency on the high—end.

    Have you had issues with a Honda Accord P1259 code? Let us know your thoughts below.

Category: Honda OBD OBDII Error Codes

About Bob Thomas

Bob Thomas is an automotive mechanic with 30 plus years experience. He is a contributor to several publications and has written many articles on automotive maintenance and repairs. He also has created many auto repair videos on YouTube.

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