Notices
Engine Management and ECU Remapping This section is to discuss the various aspects of engine management modification for your Subaru.

Engine warning light, fault code PO171

Thread Tools
 
Search this Thread
 
Old 13 June 2014, 04:43 PM
  #1  
phantomkipper
Scooby Newbie
Thread Starter
 
phantomkipper's Avatar
 
Join Date: Jul 2003
Location: Camberley
Posts: 15
Likes: 0
Received 1 Like on 1 Post
Default Engine warning light, fault code PO171

Engine management warning light came on as I was driving very slowly. My Scooby is a WRX Pro-drive 2005, totally standard and trouble-free. It has a hunting, snatchy tick-over and is snatchy at low throttle openings, i.e. in traffic.
Took it the Subaru main dealer to fix the problem and service it (£340) but the didn't fix the problem and said it was indicating lean running, possibly an intermittent fault with the air flow meter. Engine light came back on before I got home.

I flipped the bonnet, popped the air box cover and found that the air filter was extremely distorted, the filter's metal sides were bowed, letting air past and the element was a real mess, all lifted up, as though the intake suction had ripped it apart. Rather like the element had gradually blocked and could not deliver the air the engine needs when I welly it.

I connected my fault meter to the car and got PO171, lean running indicated.

I have ordered a K&N performance replacement that replaces the dirty old paper one.

Could this have been the cause of my lumpy and lean running?

Nick

Last edited by phantomkipper; 14 June 2014 at 06:09 PM.
Old 15 June 2014, 12:05 AM
  #2  
has-scooby
Scooby Regular
iTrader: (7)
 
has-scooby's Avatar
 
Join Date: Aug 2006
Posts: 157
Likes: 0
Received 0 Likes on 0 Posts
Default

had the same fault recently mate it happened to be a split in the induction hose to the turbo. check all hoses for splits or any that have come loose.
Old 01 July 2014, 05:43 PM
  #3  
phantomkipper
Scooby Newbie
Thread Starter
 
phantomkipper's Avatar
 
Join Date: Jul 2003
Location: Camberley
Posts: 15
Likes: 0
Received 1 Like on 1 Post
Cool Running Lean code PO171

I got a K&N performance air filter and it was the answer. The car doesn't ****** at low rpm, ticks over like an old diesel canal boat, breathes easily again and the revs rise quickly into licence losing territory. My local Subaru specialists also spotted the exhaust leaked from the middle section (mild steel) and from a fracture round the rear box junction (SS). Got a new straight-thu (SS) mid section, and it burbles sweetly and goes like a dream.
My main dealer will never see me again!
Nick
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bugeye269
General Technical
2
27 September 2015 11:05 PM
aaron_ions
General Technical
1
17 September 2015 10:42 AM
Bingerz1981
General Technical
1
15 September 2015 10:03 PM
slimwiltaz
General Technical
7
12 September 2015 07:54 AM



Quick Reply: Engine warning light, fault code PO171



All times are GMT +1. The time now is 07:24 AM.