If you’ve driven a Honda, you probably had to learn about the VTEC system which is short for Variable Valve Timing and Lift Electronic Control. This is a system that controls how air moves through your engine’s intake valves. It uses oil pressure to control when these valves open and close in order to improve performance.
When there’s a problem with the VTEC system, it can cause an error code P1259 on your dashboard.
Table of contents
- What is The P1259 Code?
- Causes of The P1259 Code
- 2. Poor Electrical Connections in the VTEC Circuit
- 3. Defective VTEC Solenoid
- How to Diagnose The P1259 Code
- How to Fix The P1259 Code
What is The P1259 Code?
This code indicates that there is a problem with the VTEC oil pressure switch or at the VTEC solenoid valve circuit. It also shows that the engine control module (ECM) which monitors the VTEC oil pressure switch through the CAN network has determined that there is an issue.
The P1259 code is a generic trouble code that can cause several problems in the powertrain control module (PCM). The PCM is responsible for communicating with other parts of your vehicle to ensure all systems are working together properly.
When one of these sensors or actuators does not respond correctly, it will set off the OBD2 check engine light and trigger this error code
The most common cause of this problem is a bad PCM or faulty transmission sensor. Other causes include poor wiring/connector between sensors/actuators, poor grounds at both ends of each wire; shorted wires going to TCM relay #1, or damaged PCM itself due to corrosion or overheating from lack of coolant flow through the radiator cap.
Causes of The P1259 Code
1. Low Oil Pressure
There are a number of reasons why you may be seeing the P1259 code. The first is low oil pressure or low engine oil level.
If your car’s engine has been running for a while and the oil levels have dropped, it can cause your vehicle to throw this code as a warning.
If this is the case, then you need to refill your engine with more oil. Service manuals also suggest that you check if there are any mechanical problems with your vehicle such as worn-out bearings or seals that could cause excessive wear on your motor and lead to increased friction between moving parts.
2. Poor Electrical Connections in the VTEC Circuit
There are several possible causes for this code, but the most common is a poor electrical connection in the VTEC circuit. This can happen if there is damage to any of the wiring harnesses or connectors, so it’s important to check them over carefully.
Wires will also wear out over time. This may cause an intermittent connection issue that could be misdiagnosed as a P1259 code. Heat and corrosion can also contribute to intermittent problems with power distribution throughout your vehicle’s electrical system, so keep an eye out for signs of wear or damage as well as discoloration or other signs of oxidation on any wires or connectors that might be susceptible to it.
3. Defective VTEC Solenoid
The VTEC solenoid is a coil that controls the valve timing on your Honda. The VTEC (Variable Valve Timing and Lift Electronic Control) system is an electronically controlled variable valve lift mechanism that increases engine power and efficiency by switching between two different valve timing maps. This allows for improved fuel economy and reduced emissions at low speeds, along with increased performance at higher speeds.
The VTEC solenoid can be replaced if it fails or begins to fail with age and use. The part itself is relatively inexpensive, but because it must be removed from under the hood of your car, you can expect to pay a little more than usual for repairs due to labor costs associated with this type of job.
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How to Diagnose The P1259 Code
1. Check to See If The Engine Light is On
If your car’s engine light is on, you’re going to want to check it out. Your vehicle’s computer has detected something that might be wrong with your engine, so it’s best to take a look at what you think needs fixing before driving yourself crazy by trying different parts and hoping they solve the problem.
If the light is flashing or blinking, then there’s likely some sort of error with your car that needs attention right away but if it just stays a solid color, like orange or yellow, then there may not be anything wrong at all (that doesn’t mean you shouldn’t still check).
2. Check the VTEC Solenoid
The VTEC solenoid is located on top of and to the left of your engine. It looks like a small box with a rubber cap on it, and it might be covered in dirt and grime if you don’t keep up with your car maintenance.
The best way to diagnose a blown VTEC solenoid is by visually inspecting it and then checking its electrical connection by using an ohmmeter or continuity tester.
If there are no obvious signs of damage or corrosion on either end of the wiring harness and there’s no resistance present when you connect one lead wire across each terminal’s two terminals, then you’re probably okay but if either test gives an indication that there is something wrong with your VTEC solenoid, then you’ll need to replace it before driving again.
How to Fix The P1259 Code
1. Reset The Code
The first thing to do when you get a P1259 code is to reset the powertrain control module (PCM). If it comes back, then go ahead and clear the code. If not, then you might have a problem with your throttle position sensor or air intake temperature sensor.
If you’ve already tried this step and your check engine light is still on, then you can use an OBD2 scanner to read your codes. You may also want to take it to a mechanic or diagnostic center if possible so they can diagnose your vehicle’s issues more thoroughly.
2. Replace The VTEC Oil Pressure Switch
To replace the VTEC oil pressure switch, you’ll need to:
- Remove the faulty VTEC oil pressure switch. The VTEC oil pressure switch is located on top of the valve body and connected to a red connector. Remove it by pressing down on its locking clip and pulling it out of place.
- Install the new VTEC oil pressure switch in its place. Connect it back into place with a locking clip and make sure that it locks into position when pushed down into place.
- Test your work by connecting your OBD2 scanner to your car’s computer system again and run another diagnostic test for an engine code P1259 error code related to excessive amounts of air entering through the engine control system; if this is successful, then you can be confident that everything worked correctly.
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3. Replace Faulty VTEC Solenoid
The VTEC solenoid is a device located in the engine compartment, to the left of the battery. It operates by opening and closing with a camshaft lobe; when activated, it allows oil pressure to be applied to various components of your engine.
When this part malfunctions, it can cause your Check Engine Light (CEL) or Malfunction Indicator Lamp (MIL) light to turn on.
Once you have diagnosed that your car is showing the P1259 code due to a faulty solenoid then a replacement will likely be needed. A replacement part will likely cost between $100-$200 from an online retailer like Amazon or Autozone without requiring any special tools or skills beyond those needed for basic maintenance work tasks like changing oil filters etc.
So aside from labor costs associated with removing old ones before installing new ones into place which may vary depending upon where these installations take place, this fix should only cost about $200-$250 total including taxes/shipping charges.
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A display of an Obd Code P1259 indicates either of the following: low oil pressure, poor electrical connection in the VTEC circuit, or defective VTEC solenoid. Whatever the case, it’s best you take your car to a professional auto mechanic for repairs.
Ugo is a passionate car enthusiast with a Bachelor of Electrical and Electronics Engineering degree and hands-on experience in troubleshooting and fixing automobiles.
I combine my electrical and mechanical engineering knowledge with practical skills to address car-related issues.
My love for cars and dedication to educating others led to the creation of Fixandtroubleshoot.com!