VTEC Solenoid Inspection

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What makes Honda engines amazing?

"vtec just kicked in yo"

But what if your little race against the Mustang next to you ends up with a lighting up engine control light and a missing "kick"? Your ECU wants to inform you about a malfunction in the VTEC system.

Most common DTC (Diagnostic Trouble Code) here is:

DTC 1259 - VTEC System Malfunction

If you get this error code check at first the VTEC solenoid. It's not difficult and can be done in about thirty minutes. Let's jump right into this:

#1 Removal

Removing and checking the solenoid is no big job. You only need a ratchtet or a wrench. The solenoid is located at the backside of the engine, just above the exhaust header. It's mounted to the cylinder head with three bolts. The little bolt on the right side hasn't to be removed, it just attaches the headshield to the solenoid but you can remove the whole part as once.

1) Unplug the two plugs of the engine harness which are connected to the solenoid itself and to the oil pressure switch.

2) Unscrew the three bolts which connect the solenoid to the cylinder head. If the engine is installed in the car, it's a bit difficult to locate the bolts because you can't see them from above. A little mirror eases the process a lot. Hold the solenoid with one hand when it comes to unscrew the last of the three bolts.

3) Take the whole part out. Make sure not to tip the inlet of the solenoid downwards because there's still engine oil in it.


#2 Inspection & Cleaning

Let the remaining engine oil phase out the solenoid. There's a little filter with a metallic sieve on the inlet side. This sieve protects the solenoid from dirt particles in the engine oil.

In some cases it could be clogged up. The oil can no longer pass the sieve how it should be. As a result of this, the VTEC system can't build up oil pressure and the VTEC isn't engaging properly. In other words: No kick 🙁

If your solenoid's sieve is clogged up, replace the filter part. The part number is: 

HONDA 15815-RAA-A02 Spool Valve Filter

In addition the solenoid should be cleaned out with brake cleaner. The chance is high that there are remaining dirt particles in it. Of course you should change engine oil and engine oil filter too.


#3 Reassemble

Refer to the removal procedure in reverse order. Make sure to clean the sealing surface on the cylinder head before. The bolts have to be tightened as follows:

7.2 lbs ft / 9.8 Nm

... or just handtight.

After you'd plugged the two plugs back in you can start up the engine. Check for leakage while it's running.

You're all done!

Check out our VTEC solenoid inspection video to see the full procedure in action:



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