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Old 09-30-2012, 08:29 PM   #3
BC_ZX3
DTC P0606
 
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What I Drive: 2001 Red ZX3 Turbo

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P0171s are usually a lean condition caused by a vacuum leak of some sort after the MAF. On the Duratec motor, the PCV line is particularly difficult to inspect and replace, iirc. There is a thread on FF with pictures. Edit: thread here

DTC definition from Ford:

P0171 - System too lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

For lean and rich DTCs:

Fuel system:
Excessive fuel pressure.
Leaking/contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Vapor recovery system.

Induction system:
Air leaks after the MAF.
Vacuum Leaks.
PCV system.
Improperly seated engine oil dipstick.

EGR system:
Leaking gasket.
Stuck EGR valve.
Leaking diaphragm or EVR.

Base Engine:
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.

A SHRTFT-1,2 PID value between -25% to +35% and a LONGFT-1,2 PID value between -35% to +35% is acceptable. Reading beyond these values indicate a failure.
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