Honda

Nov 19, 2023

Some 2007-08 Honda Civic models may illuminate the Check Engine light and store trouble code P0456 (EVAP system leak) in the PCM.

One likely cause, reports Honda, is an internal glitch in the canister purge valve. Replacing the purge valve with an upgraded design, Part No. 36162-RNA-A01, H/C 8048126, should eliminate the concern.

Start your diagnosis by locating the purge valve, which you'll find underneath the center portion of the cowl cover, as shown in the illustration above. Once located, disconnect its vacuum hose and attach a vacuum pump to the nipple. Now draw 5 in-Hg vacuum and look at the gauge. The purge valve should hold vacuum for at least 10 seconds.

If it does, continue searching for the cause of the evaporative system leak. If the valve doesn't hold vacuum, it's defective and should be replaced with the upgraded unit.

Begin the fix by removing the cowl cover. Next, disconnect the electrical connector and remove the two retaining bolts, followed by the purge valve itself. Now push the new valve into the throttle body, ensuring it's fully seated and isn't cocked. Install the two retaining bolts finger-tight.

Tighten the upper bolt first, then the lower bolt. Make sure you follow this sequence or the new purge valve could leak! To complete the repair, reconnect the vacuum hose and electrical connector to the valve, install the cowl cover and clear the trouble code from computer memory.

"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].

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