Hello,

Looking for an answer to a strange question about this occasional code I am getting.

I recently changed the battery in my 2001 Lingenfelter 427 Z06. The battery was deader than dead. I got the car out and drove it a couple of miles afterwards and noted that the motor was running pretty rough, it sounded poor. Eventually, I got the dreaded flashing check engine light. A check of the DIC showed the P0174 C code. I brought the car home, and checked the hoses around the MAF and didn't see anything out of the ordinary. I wiggled the hoses though just to make sure, and started the car again. It then had a steady check engine light, and showed the P0174 H C code. I found a thread yesterday that described why the H and C codes would be on, but can't remember the reason.

Anyways, I then pulled the hoses, re-connected them, re-set the battery, and took off for a short low-speed test drive. During the test drive, I noted that the check engine light would only come on when the RPMs were around 2000. I also noticed that the idle would go to hell when barely stepping on brakes backing out of the driveway. I'm sure that it is the PCV system and I need to double and triple check the hoses, but is there anything else you guys can think of that I need to check on? I plan on cleaning the MAF this week as well as changing plugs. If all else fails, it's BACK TO THE DYNO we go for a re-tune!

Thanks for any help/advice!

 

No guesses?

 

According to GM's Service Information P0174 is Fuel Trim System LEAN Bank 2. There is also a bulletin for that code, I would start there first. Or if you can get your hands on a scanner take a look at the 02 sensors.

Condition
Some customers may comment on any of the following various driveability symptoms:

• Extended Crank Time

• Hard to Start

• MIL/SES Illuminated with DTCs

• Hesitation

• Lack of Power

• Surge or Chuggle

• Rough Idle

• Light or Intermittent Misfire

Cause
Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.

Correction
Fuel injector restrictions, deposits can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened. As a long term solution, and to prevent reoccurrence, customers should be encouraged to use Top Tier Detergent Gasoline . For further information on Top Tier detergent gasoline and fuel retailers, please refer to the following Corporate Bulletin Numbers:

• 04-06-04-047G (U.S. Only)

• 05-06-04-022C (Canada ONLY)

Notice: GM UPPER ENGINE AND FUEL INJECTOR CLEANER is the only injector cleaning agent approved for use with General Motors fuel system components. Other injector cleaners may cause damage to plastics, plated metals or bearings. General Motors has completed extensive laboratory testing of GM Upper Engine and Fuel Injector Cleaner, and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is followed correctly.

Injector Cleaning Procedure
The following tools, or their equivalent, are required:

• CH-47976 Active Fuel Injector Tester (AFIT)

• J 35800-A Fuel Injector Cleaner

• J 37287 Fuel Line Shut-off Adapter

• J 42964 Fuel Line Shut-off Adapter

• J 42873 Fuel Line Shut-off Adapter

• * One bottle of GM Upper Engine and Fuel Injector Cleaner, P/N 88861802 (in Canada, P/N 88861804)

• * One bottle of GM Fuel System Treatment Plus, P/N 88861011 (in Canada, P/N 88861012)

 

Something quick and easy is to clean the MAF. I had both lean bank codes and cleaning the MAF took care of them. Ive been 1000+ miles without them showing up again.

 

Thanks guys, will work on it this week!!!