Sevice Engine Light On-Help
12-04-2008, 04:42 PM
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Sevice Engine Light On-Help Driving home today my car threw on the dreaded 'Service Engine Soon' light, so I cruised on over to AutoZone. They scanned it and 'P0174' came up. He printed out the description which said: Fuel Trim Bank Two Condition, a rich or lean air/fuel ratio cond. on engine bank two. Can anyone give me a little more description as to what that means? And is ok to drive 40 miles round trip to work tomorrow?
12-04-2008, 07:41 PM
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I would look for vacuum leaks around your intake manifold.
Bank 2 is the passenger side of the engine, Cyl. 2,4,6, and 8. This code is set because the PCM "sees" too much oxygen for the amount of fuel on that side of the engine. A couple of things may cause this. I will list the more common failures. First, you need to understand that the o2 sensor reports this info to the PCM. Here we go. If you truly have a lean condition it may be caused by a partially plugged/dirty injector or two on that side. If you have a "false" lean condition this may be due to an exhaust leak on the passenger side exhaust manifold, AIR pipe, or EGR pipe. The exhaust leak may allow outside o2 into the exhaust stream. This free oxygen is picked up by the o2 sensor and reported back to the PCM. Some misfires will also trick the PCM into a false lean condition. Since the air/fuel mixture is not burned it makes its way into the exhaust stream. Remember the o2 sensor cannot "see" raw fuel it can only sense the oxygen. Misfires generally set misfire codes like P03xx, but not always. Tiny vacuum leaks near the intake ports on the passenger side of the intake manifold or injector o-rings. These vacuum leaks, however, generally produce misfires, but not always. Finally, we get to the o2 sensor itself. If the o2 sensor is lazy or biased rich(broken) it could send an incorrect signal to the PCM as well. Good luck.
P.S. AIR=Air Injection Reactor
EGR=Exhaust Gas Recirculation
PCM=Powertrain Control Module (car's computer)
Bank 2 is the passenger side of the engine, Cyl. 2,4,6, and 8. This code is set because the PCM "sees" too much oxygen for the amount of fuel on that side of the engine. A couple of things may cause this. I will list the more common failures. First, you need to understand that the o2 sensor reports this info to the PCM. Here we go. If you truly have a lean condition it may be caused by a partially plugged/dirty injector or two on that side. If you have a "false" lean condition this may be due to an exhaust leak on the passenger side exhaust manifold, AIR pipe, or EGR pipe. The exhaust leak may allow outside o2 into the exhaust stream. This free oxygen is picked up by the o2 sensor and reported back to the PCM. Some misfires will also trick the PCM into a false lean condition. Since the air/fuel mixture is not burned it makes its way into the exhaust stream. Remember the o2 sensor cannot "see" raw fuel it can only sense the oxygen. Misfires generally set misfire codes like P03xx, but not always. Tiny vacuum leaks near the intake ports on the passenger side of the intake manifold or injector o-rings. These vacuum leaks, however, generally produce misfires, but not always. Finally, we get to the o2 sensor itself. If the o2 sensor is lazy or biased rich(broken) it could send an incorrect signal to the PCM as well. Good luck.
P.S. AIR=Air Injection Reactor
EGR=Exhaust Gas Recirculation
PCM=Powertrain Control Module (car's computer)
