What does Bank one system too rich mean? This is code P0172B that shows under check engine light which is keeping my 1996 volvo from passing inspection.

SOURCE: Want to know what PO172 System too rich bank 1

it means your cars computer is pumping too muchgas into your motor because it thinks the engine is either running lean possibly due to faulty o2 sensors or that the coolant temp sensor is giving false readings and the ecm thinks the car is still too cold.

SOURCE: O2 Sensor Problems-1996 Isuzu Trooper

they are very easy to replace .
all you need to do is go to autozone and get the right parts.
then you will find the old parts on the exhaust system.
unplug the first one you find and unscrew it from the exhaust and refit the proper replacment part.plug wire back in.thats all you will need to do on the second one also.after that your done.ask auto zone after that to reset your codes for free with the code checker.then get a can of carb cleaner and spray out the throttle body of all the black carbon around the throttle plate.use a clean rag only.make sure its clean around the plate.
thewn fill your gas tank with supperunlead dont get the crappy gas any more cause it causes the carbon to build up.plus you will get better gas mileage.now your ready for an inspection sticker.
hope this helps
keep me posted
jm

SOURCE: Diagnostic failed code reads PO172B Fuel Trim

Basically this means that an oxygen sensor in banks 1 and 2 detected a rich condition (too little oxygen in the exhaust).

A code P0172 may mean that one or more of the following has happened:
· The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
· There could be a vacuum leak
· There could be a fuel pressure or delivery problem
Possible solutions include:

• Inspect all vacuum and PCV hoses, replace if necessary
• Clean the MAF sensor. Consult your service manual for its location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner
  Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
• Inspect fuel lines for cracks, leaks, or pinches
• Check the fuel pressure at the fuel rail
• Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
• Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

SOURCE: I have a 97 Chevy Tahoe 4x4 with a 5.7 engine the

Hey. How many miles on it. If over 100,000, it may need new O2 sensors but unlikely both would go out of spec at the same time. You will need to install a scan tool with data stream abilitys. The pressure regulator could be ruptured which will drastically richen up both banks. If no tool, locate the pressure regulator, usually on the right side at the end of fuel rail. Make sure the vacuum line is attached and pulls vacuum. Unhook the line. The motor should sound very different and then correct itself when hooking the line back up. If there is no vacuum at the line, check for a broken or cracked area. Never overlook the simple stuff. Also need to check coolant temp sensor accuracy. It can be in tolerance but still read incorrect coolant temp. There are numerous other items that will cause a rich condition but check these first. TJ.

SOURCE: Check engine light (emission system service required) Help?!?!

There may be problem with the mass air flow sensor (very common with Volvo). This causes the fuel system to malfunction.

You may have noticed increased fuel consumption, loss of power and general 'lazyness'.

Better to take it to authorized Volvo service for a checkup/fix.