NEED HELP P0171

[bazza7548]

Hi guys,

Need you expert opinions, recently I have noticed the the engine has gone from 600 rpm rough idle to a smoother idle of 900 (no check engine light) After plugging it in to a OBD there is a code of P0171 also noticed the the coolant temp is 2 ticks to the left around 86c. (My cluster is in kpa and Celsius)
Could these 2 issues be related or separate? I live in Suadi and parts are a nightmare.
Cheers guys in advance

baz

 

[Matt]

They not related issues. Is there a way to read what the Bank 1 O2 sensor is doing in real time? Just based on the code I'd say it's getting lazy and needs to be replaced but real time data to see if it's bouncing up and down fast-ish (which it should be) would tell for sure. The coolant temp could be your thermostat starting to stick open. If you get a P0128, that's time to replace it.

 

[bazza7548]

They not related issues. Is there a way to read what the Bank 1 O2 sensor is doing in real time? Just based on the code I'd say it's getting lazy and needs to be replaced but real time data to see if it's bouncing up and down fast-ish (which it should be) would tell for sure. The coolant temp could be your thermostat starting to stick open. If you get a P0128, that's time to replace it.

 

[bazza7548]

View attachment 96045

Hi Matt

looks like your right about thermostat, just had P0128 come up on obd

 

[Mooseman]

P0171 could simply be a vacuum leak somewhere. This thread is a good source of info:

NEED HELP - P0171 Lean Code

2003 TB EXT 4.2l is throwing code P0171 after driving for about 20 minutes at speeds of 55-70. The vehicle has almost 160K miles on it, with a remanufactured engine that only has 20K miles on it. Over the past 3 months this is what has happened. I was getting a code P0340 (Camshaft position...

gmtnation.com

 

[TJBaker57]

Somewhere I read a TSB or similar stating the 900 rpm idle and the p0171 ARE related. Now I just have to find that again!!

 

[TJBaker57]

Somewhere I read a TSB or similar stating the 900 rpm idle and the p0171 ARE related. Now I just have to find that again!!

As usual, I can't find a damned thing!

The low ECT could be a contributing factor.

P0171 is set when the fuel trim index is over 146. (There's a PID for that over in the scanner section).

 

[Matt]

Somewhere I read a TSB or similar stating the 900 rpm idle and the p0171 ARE related. Now I just have to find that again!!

I was talking about the P0171 and low coolant temp.

 

[TJBaker57]

I was talking about the P0171 and low coolant temp.

I realized that as an afterthought.