PCM Codes P0172 & P0175

[Craig-o]

I have reviewed previous posts, and found the resources to help me identify the meaning of the 2 codes that my car has thrown, but what I'm not sure is what to try before taking it to a "professional".

The 2 codes are: P0172 Fuel Trim System Rich Bank 1, and P0175 Fuel Trim System Rich Bank 2

These came up the first time, while sitting in bumper to bumper traffic Friday evening on my way out of town. I should mention that I recently filled up (only ~6 gallons) about 30 miles previous at an independent gas station. I cleared the codes before my return trip (put ~7 gallons of Chevron 91) in to fill it, and it threw them again.

Any ideas on a remedy before I take it to a shop and have them look at it?

Craig

 

[yellow_2002_germany]

Looking at the service manual for my 2002, there is a list of 10 conditions which need to be met to run the DTC.

In the diagnostic aids section it says fuel contamination such as water or alcohol will affect the fuel trim. Also, a malfunctioning MAF sensor can cause a rich condition. It adds in a different section that an EVAP canister that is saturated will cause a rich condition.

In the table of troubleshooting it says to visually check the MAF screen for blockage. (When I changed over to a Blackwing I did find a few dead bugs on my MAF screen).

I think if you let it get almost empty and put in a tankfull of some good gas, you mentioned Chevron, you might give it another try.

Hope I have given you a bit of a starting point.

 

[Moval49er]

Looking at the service manual for my 2002, there is a list of 10 conditions which need to be met to run the DTC.

In the diagnostic aids section it says fuel contamination such as water or alcohol will affect the fuel trim.
I think if you let it get almost empty and put in a tankfull of some good gas, you mentioned Chevron, you might give it another try.

Hope I have given you a bit of a starting point.

I agree. Also, put in some Techron - I have started using it every oil change and it has made a difference in clatter at start-up (Techron is recommended by Chevy to decarb) and is keeping my senders in the game after having them go bad. I did Techron for 3 tanks to start (my '02 is at 34,000), then do it at the 5K oil change intervals.

Good luck,

Lee

 

[TODD L GRIFFITH]

What type of mods. do you have?