What Does code Mean?

OBD II fault code P1259 is a manufacturer particular code the is characterized by carmaker Honda together “VTEC device Circuit fault (Bank 1)”, and is collection on these applications once the PCM (Powertrain control Module) detects a defect, malfunction, or failure in the electrical control/monitoring device of the VTEC mechanism on financial institution 1. Keep in mind that “Bank 1” refers to the financial institution of cylinders that has cylinder #1 top top V-type engines.

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“VTECH” stands for Variable Valve Timing & Lift Electronic Control, and also is the name given to the proprietary system Honda supplies to change the lift and also duration that the engine valves top top VTEC equipped engines.

The VTEC mechanism uses two (or occasionally three) camshaft lobe file that can be selected hydraulically to rise the volumetric effectiveness of the engine. Together a useful matter though, VTEC have to not be confused with variable Valve Timing systems that turn camshafts family member to a reference allude in order come either breakthrough or retard the valve timing.

In regards to operation, the VTEC system most generally uses two camshaft lobe file per collection of valves. One profile is designed to enhance power and fuel economic situation at low engine speeds, if the other profile is draft to boost airflow, and also hence engine strength at engine speed above around 4000 RPM. In practice, the three equivalent valve lifters (aka, rocker arms) deserve to move independently of every other; at low engine speeds, two valve lifters operate the valves, if the third rocker eight is merely complies with the video camer lobe, yet cannot activate the valves.

When conditions allow, frequently at high engine speeds above around 4000 RPM, the PCM opens up an oil regulate solenoid that allows pressurized engine oil come act on a sliding locking pin the locks the 3 valve lifters together. This enables the (middle) high-lift electronic came lobe to deliver its motion to the 2 adjoining valve lifters via the locking pin, thereby raising both the lift and duration the the valves. Once the engine rate drops below about 4000 RPM, the PCM clears oil press from the locking pin, i m sorry disengages the center valve lifter indigenous the adjoining lifters, and the engine reverts to utilizing the low-lift lifters.

In practice, the PCM uses input data native the engine speed sensor, throttle position sensor, devoted VTEC oil pressure switch, and also several various other sensors to determine the switching suggest between high and also low elevator valve operation, meaning that the switching process does not require any kind of inputs indigenous the driver, and is therefore reasonably seamless.

It have to be listed though if that code P1259 specifically refers to a difficulty in the VTEC systems’ control/signal/monitoring circuit, part mechanical failure modes can add to this code being set and stored.

Where is the sensor located?

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The image above shows the ar of the VTEC oil regulate solenoid top top a Honda public engine. However, the actual location an figure of VTEC oil regulate solenoids differ somewhat between Honda applications, therefore consult the hand-operated for the affected application for details top top the ar of the solenoid, and also the routing, color-coding, and function of each wire in the oil regulate solenoid’s control circuit. Failure to recognize wires correctly will cause a misdiagnosis, and also the possible unnecessary instead of of parts and components.

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What space the common causes of code ?

As declared elsewhere, password P1259 refers to an electrical issue in the VTEC regulate system, and also all diagnostic procedures for this code have to start through a thorough visual inspection that all connected wiring and connectors. Nonetheless, some various other common causes of password P1259 might include the following-

Damaged, burnt, shorted, disconnected, and corroded wiring and/or connectorsDefective VTEC oil regulate solenoidDefective VTEC oil press switchLow engine oil levelDirty, degraded, or unsuitable engine oilFailed or failing PCM, however note that due to the fact that this a rarely event, the fault need to be sought elsewhere before any control module is replaced

NOTE: when there room some exceptions, the general ascendancy is the if the password sets at, or just over idling speeds, the fault is brought about by a general electric issue, when if the code sets above about 4000 RPM, the fault practically invariably entails insufficient oil pressure, or a fail of the VTEC oil push sensor.