did a lot of work got a bunch of codes help!

[mikeg216]

I did a full tune up on my poorly running explorer and now i have more trouble codes then when i started

did full tune up

Plugs ford plugs

wires from ford

coil pack replaced brand new

idle air controller brand new

egr valve brand new

mass air flow sensor brand new

four brand new oxygen sensors

pcv valve brand new

new tranny pan filter gasket and fluid and lucas tranny conditioner

lucas in the front and rear diff

ford semi synthetic 5-w30 oil 1 quart lucas oil conditioner ford motorcraft filter and oil pan gasket

brakes pads rotors and wheel hub assembly, it failed going down the road that was fun!

Now on to the trouble codes!

p0141

heater condition ( Heated oxygen sensor bank one sensor two)

possible causes faulty sensor bank one sensor two
poor connection
check circuit fuse

p0136

circuit condition ( heated oxygen sensor bank one sensor two)

possible causes oxygen sensor defective
fuel system running rich/lean
engine misfire condition
fuel pressure high/low fuel pump or pressure regulator

p0303

cylinder misfire detected on cylinder number three

possible causes ignition system plugs wires or coil
vacuum leak
injector fault
high/low fuel pressure
p0171

fuel trim bank one condition running rich/lean

possible causes oxygen sensor defective
ignition misfire
fuel injector problem
questions

Bank one sensor two is it driver or passenger side? and is it before or after the cat

Cylinder 3 drivers side or passenger side? and is it the one at the firewall on the most front one.

Please let me know where i should start trouble shooting these problems. Thanks for your help guys!
Mike Gaebelein

 

[yavapaires]

I did a full tune up on my poorly running explorer and now i have more trouble codes then when i started

did full tune up

Plugs ford plugs

wires from ford

coil pack replaced brand new

idle air controller brand new

egr valve brand new

mass air flow sensor brand new

four brand new oxygen sensors

pcv valve brand new

new tranny pan filter gasket and fluid and lucas tranny conditioner

lucas in the front and rear diff

ford semi synthetic 5-w30 oil 1 quart lucas oil conditioner ford motorcraft filter and oil pan gasket

brakes pads rotors and wheel hub assembly, it failed going down the road that was fun!

Now on to the trouble codes!

p0141

heater condition ( Heated oxygen sensor bank one sensor two)

possible causes faulty sensor bank one sensor two
poor connection
check circuit fuse

p0136

circuit condition ( heated oxygen sensor bank one sensor two)

possible causes oxygen sensor defective
fuel system running rich/lean
engine misfire condition
fuel pressure high/low fuel pump or pressure regulator

p0303

cylinder misfire detected on cylinder number three

possible causes ignition system plugs wires or coil
vacuum leak
injector fault
high/low fuel pressure
p0171

fuel trim bank one condition running rich/lean

possible causes oxygen sensor defective
ignition misfire
fuel injector problem
questions

Bank one sensor two is it driver or passenger side? and is it before or after the cat

Cylinder 3 drivers side or passenger side? and is it the one at the firewall on the most front one.

Please let me know where i should start trouble shooting these problems. Thanks for your help guys!
Mike Gaebelein

Does the truck run without any problems? Double check, triple check ALL your wiring and electrical connections.Drive the truck, if it drives OK, then disconnect the battery, wait a few minutes, reconnect the battery and drive it again There should be no codes if everything hooked up correctly. WARNING- there will be a bunch of people disagreeing with this post. It's your truck, you asked for help, these are my suggestions. It is what I would do if it were mine. Mine runs good without major problems, and I have done this procedurs many times.

 

[mikeg216]

Does the truck run without any problems? Double check, triple check ALL your wiring and electrical connections.Drive the truck, if it drives OK, then disconnect the battery, wait a few minutes, reconnect the battery and drive it again There should be no codes if everything hooked up correctly. WARNING- there will be a bunch of people disagreeing with this post. It's your truck, you asked for help, these are my suggestions. It is what I would do if it were mine. Mine runs good without major problems, and I have done this procedurs many times.

i did that after i replaced my wheel hub assembly and fixed my exhaust leak thats when these codes popped up there is a vacuum leak i can hear on passenger side but cannot find i sprayed down the whole side of the engine with start fluid and i got nothing. And the engine is running very rich im getting about 8 mpg and i can confirm there is a misfire as shown by the cel flashing, its weird though because i changed the spark plugs and the end of october but now its showing a misfire?

 

[2000StreetRod]

O2 sensor connection/wiring

Which engine - OHV or SOHC V6?

P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0171 System too Lean (Bank 1)

Bank 1 is the passenger side. Sensor 2 is the post cat sensor. It is either bad, not connected properly, or the wires are shorted or broken. Most likely just not connected. Your PCM might be running in open loop since it knows the O2 sensor isn't working.

Check the connection to the MAF sensor. If that doesn't help put the old one back on to see if new one is defective.

P0303 Cylinder 3 Misfire Detected
Passenger side next to firewall

 

[mikeg216]

Which engine - OHV or SOHC V6?

P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0171 System too Lean (Bank 1)

Bank 1 is the passenger side. Sensor 2 is the post cat sensor. It is either bad, not connected properly, or the wires are shorted or broken. Most likely just not connected. Your PCM might be running in open loop since it knows the O2 sensor isn't working.

Check the connection to the MAF sensor. If that doesn't help put the old one back on to see if new one is defective.

P0303 Cylinder 3 Misfire Detected
Passenger side next to firewall

1998 sohc sport cant believe i posted all that info and forgot to specify what engine!

 

[mikeg216]

1998 sohc sport cant believe i posted all that info and forgot to specify what engine!

in the morning i think i should just swap out the post cat 02 since its got a lifetime warranty and put the old maf back in and start from there watcha think?

 

[2000StreetRod]

current codes?

I agree with yavapaires to make sure you have the current codes. If so, then I would first check the connection on the O2 sensor before attempting to swap it. As I recall it is in a difficult to access location. If you change more than one thing at a time then you won't know what fixed the problem.

A post cat O2 sensor should not have a significant affect on the Air/Fuel ratio unless the PCM stays in open loop because of it. If the MAF sensor is bad then it should affect both banks. Some members crossed their O2 connectors when they replaced them - connected the left harness to the right sensor and the right harness to the left sensor. That usually results in too lean and too rich codes which you don't have. I don't remember what codes you get if you swap the wiring between the precat and postcat O2 sensors on one bank but it really confuses the PCM.

 

[2000StreetRod]

O2 sensor wiring

Here's the O2 sensor wiring for my 2000 Sport. It may help you sort things out.

Bank 1 > passenger (right) side
Bank 2 > driver (left) side

HO2S #11 (Bank 1 Pre-cat)
Gray/Light Blue (O2 voltage to PCM)
Orange (sensor return common)
Red/White (Heater output to PCM)
Light Blue/Orange (heater supply)

HO2S #21 (Bank 2 Pre-cat)
Red/Black (O2 voltage to PCM)
Orange (sensor return common)
Yellow/Light Blue (Heater output to PCM)
Light Blue/Orange (heater supply)

HO2S #12 (Bank 1 Post-cat)
Red/Light Green (O2 voltage to PCM)
Orange (sensor return common)
White/Black (Heater output to PCM)
Light Blue/Orange (heater supply)

HO2S #22 (Bank 2 Post-cat)
Purple/Light Green (O2 voltage to PCM)
Orange (sensor return common)
Tan/Yellow (Heater output to PCM)
Light Blue/Orange (heater supply)

 

[mikeg216]

Which engine - OHV or SOHC V6?

P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0171 System too Lean (Bank 1)

Bank 1 is the passenger side. Sensor 2 is the post cat sensor. It is either bad, not connected properly, or the wires are shorted or broken. Most likely just not connected. Your PCM might be running in open loop since it knows the O2 sensor isn't working.

Check the connection to the MAF sensor. If that doesn't help put the old one back on to see if new one is defective.

P0303 Cylinder 3 Misfire Detected
Passenger side next to firewall

you got it passenger side post cat sensor is not connected but since im not under the truck i cant see where to connect it to any suggestions? pics?

 

[mikeg216]

you got it passenger side post cat sensor is not connected but since im not under the truck i cant see where to connect it to any suggestions? pics?

nevermind i tried to connect the one that i had in the bung on the passenger side and the pigtail was not long enough. so i went and got the right legnth pigtail and brute forced it in there in the dark with my spelunking light and got her in there!