This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.
A P0026 trouble code means that the intake valve control solenoid circuit range/performance (bank 1) has been affected.
A P0026 trouble code is the OBDII generic code that indicates that the engine control module in the vehicle has determined that the variable valve lift solenoid that is associated with the intake valves for bank 1 takes too long to engage or is not engaging at all.
There are several key causes that can trigger a P0026 trouble code to appear on your OBDII scanner. It can be caused if the ECM activates the intake valve solenoid for bank 1, but the valves do not or cannot change to the high lift position. This can occur if the intake valve solenoid has an open or short circuit. This could also be because of the connections or wiring to the intake valve solenoid is shortened or open. One of the less common, but still viable, cause of this problem is that the ESM is defective or the connection to the ECM has loose contact.
There are certain symptoms you should be on the lookout for, should you suspect that a P0026 trouble code is the problem, or to further verify that a P0026 trouble code is what you are experiencing. The engine may have a lack of power. This would happen if the valve lift fails in the lowered position.
You may notice that the engine runs rough or stalls. This would occur if one of the two camshafts are stuck in the high valve lift position. This should cause the engine to run erratically, depending on the position that the intake valves failed in. Like many other issues in the vehicle, the check engine light should be illuminated as well.
There are several steps you a mechanic should work through in properly diagnosing a P0026 trouble code.
First, they should perform a visual check of the electrical connections of the wire harness to the bank 1 intake valve solenoid. They should then clear the code to verify the code returns before performing any further testing of the issue.
For proper diagnosis, install the test intake valve control solenoid for proper diagnosis and follow the pinpoint test to see if the valves change during the test. If it commands the test solenoid off the intake valve should go to a high lift. If it commands the test solenoid on, the intake valves should go to the low lift position. Make sure that you follow the manufacturer’s specific pinpoint tests for further diagnosis.
There are some common mistakes you should be aware of when properly diagnosing a P0026 trouble code. You need to make sure that you verify the specific failure by clearing the code and seeing if the code still presents itself after clearing the OBDII. You should not attempt any diagnosis without special tools like a test solenoid. Make sure that any pinpoint test is done step by step as this is the only way you can isolate the specific reason for the failure on the system. Do not replace any parts until you are directed by the visual or pinpoint test to do so.
How serious is this?
There are certain risks that are associated with this trouble code. If one of the camshafts is stuck in the high lift and the other in the low, the engine may start running rough. It could also stall when bringing the car to a stop. The engine may also hesitate and have a lack of power when you accelerate. The engine may also start to run hard or too lean.
What repairs can fix the code?
The first step you can take is clearing the fault codes, followed by performing a road test to verify the failure. Test the solenoid that is installed to see if the valves work as they should, replacing the intake lift solenoid. Repair or replace the connection or wiring to the intake lift solenoid. You can repair the ECM or the ECM connector as well.
Now you have a better understanding of the common causes of this trouble code, how to verify it, and a methodical way of fixing this trouble code. Make sure that you follow each step of the diagnosis and repair process to avoid any further issues.
A PDF VERSION OF THIS ARTICLE FOR LATER