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Trouble code P0172

Old  June 29th, 2012, 12:28 AM
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Trouble code P0172

I'm getting a code P0172 - system too rich bank 1.
Does anyone know what I need to check or test to find out what's causing it? I've cleared it multiple times and it keeps coming back. The van runs great.

Old  June 29th, 2012, 2:42 PM
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    Miami, FL.
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

Possible solutions include:

Inspect all vacuum and PCV hoses, replace if necessary
Cleanthe MAF sensor. Consult your service manual for it's 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)

Old  June 29th, 2012, 5:18 PM
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It will be something with the maf sensor as that calcultes air flow for the pcm (or whatever) to calculate fuel. Have you changed anything in the air intake?

Old  June 29th, 2012, 6:20 PM
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Thanks, I have removed and cleaned the MAF (at least i think that's what it was). The sensor that the air flows through that's bolted to the airbox? the only change I've made is a new air filter, but that was after the code started popping up.

Old  June 29th, 2012, 7:11 PM
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typically, when the maf is bad on a v-6 engine it will effect both banks not just one. However it is possible that only one bank is setting a code and the other is askew but not setting a code yet. You will have to check fuel trim readings to tell. Nothing is lost by cleaning it.

More common faults for only one bank setting a code is a bad 02 sensor as each bank has its own 02 sensor.

Last edited by tech2; June 29th, 2012 at 7:18 PM.

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