If you want your engine to run right, it needs to breathe freely. Unfortunately, its EGR system can get filled with gunk over time, causing it to run bad and fail emissions tests. Thankfully, there is a way to clean it out and prevent major airflow issues.
So, what are the steps to cleaning the EGR system?
According to #savagescotty, you just need to:
- Remove the engine cover and hoses
- Take off the airbox, throttle body, and intake manifold
- Clean out the passageways
- Reinstall all the parts
- Clear the codes and be on your way
If you want it broken down a bit more, no worries. Lifelong mechanic Scotty Kilmer is here to guide you through the steps one by one. By the end, your car will be back to its old self and running right on all your travels.
Steps to Fixing Trouble Code P0401
If your car recently failed its emissions test or just feels like it’s running bad, then you could have a poorly flowing EGR system. To confirm that’s the problem, hook up your scan tool and see if trouble code P0401 pops up. If so, follow these steps.
1. Remove the Plastic Engine Cover and Hoses
Scotty is working on a V6 Honda with an EGR valve just below the intake manifold. He helpfully points out that it’s actually the passageways through the intake manifold below that are the problem. The valve itself rarely goes bad.
If your car is anything like the one Kilmer is working on, you’ll need to remove the plastic engine cover before doing anything else. On most cars, it just pulls off after you take off the bolts at each corner.
Next, look around the intake manifold and remove all the hoses connected to it.
2. Take Off the Throttle Body
You’ll need to disconnect the air intake hoses going to the throttle body next. You might need to use a screwdriver to loosen the clamp before gently working the hose and airbox off.
With those parts out of the way, you can reach the four bolts on the throttle body. Use a socket to loosen the bolts, and then pull the throttle body back out of your way.
3. Take the Intake Manifold off
Look at the intake manifold to see which bolts are holding it on the engine and remove them. On the Honda that Kilmer is fixing, the intake manifold is held on by several 12-millimeter bolts. Upon removing those bolts, you can simply lift the manifold off the engine.
4. Clean out the Passageways
Flip the intake manifold over to see into the passageway leading to the EGR valve. It’s likely filled with black gunky carbon that you will need to clean out. To do so, use a throttle body cleaner and a plastic stick.
The handle of a cheap kid’s paintbrush is Kilmer’s tool of choice. Smart! Never use metal since that could scratch the mating surfaces on your engine.
Alternately spray the cleaner inside the passageway and work the gunk out with the plastic stick. Once you’re done, it will not only look clean from the outside, but you’ll also hear the cleaner spray through all the passages.
Repeat the process in the bottom part of the engine that mates up to the previously clogged passageway in the intake manifold. Since its cavity is bigger, it doesn’t need to get as clean.
5. Inspect the Gaskets and Reinstall the Parts
Inspect your intake manifold gaskets for damage or missing sections. If all looks well, you can likely reuse it. Scotty does.
Reinstall all the parts in the reverse order that they were removed. Make sure to bolt them all down securely. Once you have the plastic cover in place, you can move onto the next step.
6. Start up Your Car to See How it Drives
With everything reinstalled, you just have to go on a test drive to see how it feels. Although that won’t tell you how the emissions system is working, it will let you know if you missed any hoses or installed anything wrong.
7. Reset the Computer with the Scan Tool
After getting back from your test drive, turn off your car and reset the computer using your scan tool. Plug it into the port, which is likely located inside the fuse box area. Then, put your key in the ignition, turn it to the on position, and select ‘Clear All Codes’ on your scan tool.
Repeat the Scan to See if Any Codes Come Up
Once you’re finished with this job, use your scan tool to see if any other codes come up. If so, you might want to get into the shop for service or look up other ways to fix those codes. Either way, keep your Vehicle History close by in case you need to consult with a mechanic.
