I have a 96 mustang with 3.8..
After topping off fuel tank, I got check engine light which had error
code P1151 "manufacturer control fuel / air mixture..
I confirmed gas cap was tight, cleared error code with scanner.
Same error code keeps coming back. I've checked for dipstick tight,
oil cap tight, checked for vacuum leak using brake cleaner. EGR is
operational when direct vacuum supplied to diaphragm. I've yet to get
on a lift to check ohms of O2 wiring and sensor.
When checking I/M sensors key on engine running at operating temps,
everything shows "ready" except catalyst.... this is after a 15 minute
Car runs great...(I've reset 3 times two errors each, in the past 60
miles always same code)
Any educated ideas? The list I get from google is long from this
code.. about all sensors, egr valve, egr valve control computer,
vacuum leak downstream from mass air flow sensor etc..
I've also got to check my Hayns manual, it's all I have besides here
Here's the list from internet..
All that follows is what's on that page..
P1151 OBD Trouble Code
Technical DescriptionLack of HO2S-21 Switch, Sensor Indicates Lean
What does that mean?A Heated Exhaust Oxygen (HO2S) sensor indicating
lean at the end of a test is trying to correct for an over-rich
condition. The test fails when the fuel control system no longer
detects switching for a calibrated amount of time.
SymptomsYou will likely not notice any drivability problems.
CausesA code P1151 may mean that one or more of the following has
Short to VPWR in the harness or HO2S
Water in the harness connector
Open/shorted HO2S circuit
Corrosion or poor mating terminals and wiring
Excessive fuel pressure
Leaking/contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Air leaks after the MAF
Improperly seated engine oil dipstick
Stuck EGR valve
Leaking diaphragm or EVR
Exhaust leaks before or near the HO2S(s)
Possible SolutionsSee the above list of causes and go from there.