ERG replacement=code P0402
Lead Driver
Joined: Nov 2020
Posts: 7,128
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From: Sportsman's Paradise
On the 4.6 of this era the main reason for that code was mentioned above 11 years ago. The egr port under the throttle body plenum that bolts directly to the intake manifold gets packed with carbon build up you have to dig out.
Fleet Mechanic
Joined: Jun 2023
Posts: 1,380
Likes: 383
From: WA
Confusing thread. The title is P0402. P0402 is excessive flow. P0401 is insufficient flow. 401 could be caused by a clogged EGR port. 402 not. Looks like the thread shifted to 401 at Post #8, not really clear why.
I had the generic OBDI EGR fault code on a 1995 Pathfinder. It was the same clogged port in to the intake manifold that has been mentioned a couple of times in this thread.
P0401 - good chance it's the clogged port for the hot exhaust gases in to the intake manifold.
P0402 (the thread title topic) - something else.
I had the generic OBDI EGR fault code on a 1995 Pathfinder. It was the same clogged port in to the intake manifold that has been mentioned a couple of times in this thread.
P0401 - good chance it's the clogged port for the hot exhaust gases in to the intake manifold.
P0402 (the thread title topic) - something else.
Mountain Pass
Joined: Jul 2015
Posts: 122
Likes: 27
Pretty good thread, liked the www.Easyautodiagnostics.com link, pretty well written I'm getting that 401 code.. Have replaced the EGR with O-Rileys part, going to look at DPFE and EGR Vacume regulator
Got a 2001 F150 from an auction for $1000, so far got close to $5,000 in it and still a CEL
Got a 2001 F150 from an auction for $1000, so far got close to $5,000 in it and still a CEL
Hotshot
Joined: Jul 2020
Posts: 10,534
Likes: 2,664
From: Near Salt Lake City
401 low flow on a 4.6 is usually the clogged port
The 5.4 does not clog ports
Do those pinpoint tests for code P0401 in your case
The vacuum reservoir may be cracked, it's what is supplying the EGR vacuum, and is common
Under the rf inner fender panel and another one on the battery tray
The 5.4 does not clog ports
Do those pinpoint tests for code P0401 in your case
The vacuum reservoir may be cracked, it's what is supplying the EGR vacuum, and is common
Under the rf inner fender panel and another one on the battery tray
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