Then you probably don't have spark. check EFI fuse and relay, coil, timing, fusible link etc. You can take out one of the spark plugs and ground it to see if you have spark or not.
P0401 Defeated - with pics (2 Viewers)
- Thread starter Flank
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
tried that as well. 
i dont want to come off ungrateful i really appreciate the input. i checked fuses im gonna look at the distributor cap connections and also the wiring going to the alternator. i might slave in the original fusible link to test it out if Landtanks version is a dud and if that all checks good ill slave in the old VSV and see it that was a dud.
i dont want to come off ungrateful i really appreciate the input. i checked fuses im gonna look at the distributor cap connections and also the wiring going to the alternator. i might slave in the original fusible link to test it out if Landtanks version is a dud and if that all checks good ill slave in the old VSV and see it that was a dud.
Malleus
Far west of Siegen
I'm not trying to sound unhelpful, but at this point, your best chance to quickly solve the problem is to use the FSM troubleshooting procedure.
You can download a copy to use on a laptop. It's in the Resources section.
You can download a copy to use on a laptop. It's in the Resources section.
RiverCityDave
SILVER Star
What are your dash lights doing?
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #206
Might be time to:
A: trouble shoot via FSM - its either not getting fuel or spark - if not spark but is getting fuel, you're possibly dumping a ton of gas into your cylinders which could perhaps hydrolock?
B: Start a fresh thread as the issue to get a wider audience than just those from this specific thread.
A: trouble shoot via FSM - its either not getting fuel or spark - if not spark but is getting fuel, you're possibly dumping a ton of gas into your cylinders which could perhaps hydrolock?
B: Start a fresh thread as the issue to get a wider audience than just those from this specific thread.
i started digging into what all i did during all the installs i remembered pulling the distributor to get better access to install the alternator.... then it hit me when i fed it back into the head i must have messed with the engine timing. sure enough i was almost 180* off TDC a quick adjustment of the main pully and aligned the points with #1 cylinder and she fired up! huge head ache caused by me but im happy thats all it was. so far shes running superb and no engine code so fingers crossed that killed my P0401. on another note i have this terrible wine im not sure where its coming from. it sound like from around the power steering resi so maybe the pump? i thought it was my old alternator but that isnt the case. ill upload a video later. Thank you all for the input it really helped me rack my brain on where i went wrong!!
Here is the video of the whine. I do t wanna stray off topic so I’ll take it else where
swapped in the Manta full stainless exhaust system and now the damn p0401 code has returned.
I've a new Manta full 2.5" SS system including new headers and works nice (other than stripped manifold exhaust bolt that I need to helicoil with a leak and noisey). I also have a 401 I need to go fix!
A big thank you to @Flank for this amazing thread. I have been going through the EGR system on my new-to-me 97 LC. One thing I discovered today that I have not seen mentioned here is to check the passage in the EGR valve on the exhaust pipe side of the valve where the modulator connects. You're looking for the hose from the bottom of the modulator that runs to the EGR valve. Mine was completely blocked. It was so stubborn I had to carefully drill it out to get it open with a very small drill bit. Then I was able to work at clearing it better with larger pieces of stiff wire.
I'm not out of the woods yet as I have only done one test drive since clearing the blockage but my EGR temps seem to be acting normal now as opposed to staying super low. And also the ECU finally ran the EGR test where before clearing this blockage it seemed to be stuck in a not ready state. My P0401 code is still on but I'm hoping with some more drive cycles it will clear.
I'm not out of the woods yet as I have only done one test drive since clearing the blockage but my EGR temps seem to be acting normal now as opposed to staying super low. And also the ECU finally ran the EGR test where before clearing this blockage it seemed to be stuck in a not ready state. My P0401 code is still on but I'm hoping with some more drive cycles it will clear.
Following up on my above post - clearing that passage did in fact solve the issue. The P0401 went away and has stayed away. So if you are struggling with one that may be something to check. It's free and not too bad to access.
