Post by Jeff Strickland Post by Sam Seagate Post by firstname.lastname@example.org
On Sat, 28 Feb 2015 17:48:16 -0500, Sam Seagate
Post by Sam Seagate Post by Jeff Strickland Post by Sam Seagate Post by Jeff Strickland Post by Sam Seagate
Well, less than 6 weeks after my ordeal with the defective pcb valve,
the engine light came on yet again today. Upon scanning, I am finding
codes PO135 and PO155. I haven't yet done a data record other than
checking fuel trims which are OK. Suggestions?
It's P0, not PO, by the way.
P0 (zero) is a generic code that always means the same thing on all cars
that produce it, P1 is a code that is unique to the automaker that
produces it. The same P1 code can be produced by Ford and BMW, for
example, but the meaning can be different because the code is defined by
the automaker. A P0 code made by a Ford and a BMW would mean the same
because it is defined by the OBD II conventions.
Do you know which fuses I should check? In my owner's manual, I am
unable to find any fuses either in car or under hood for the sensors.
I do not know which fuse you need to locate. There has to be one though.
If the car has a secondary air pump, the same circuit that makes the
pump come on with Cold Engine Start, and remain running for about 2
minutes, is the circuit that powers the O2 Heaters. The heaters are only
on for a couple of minutes because the hot exhaust will make them hot.
The heaters only shorten the time that the sensors need to work
properly. If there was no heater element built into the sensor, the
sensor would eventually be hot from the exhaust.
Alright, I'll take a look at the manual shortly. Thanks. There is one
thing that has occurred to me, however. After I replaced the intake
once I changed the plugs a few weeks back, I did forget to hook up a
small harness that clips to the rear bottom side of the intake on this
car (it's a green sliding clip). In reviewing the video I used to help
me remove the manifold, the mechanic talks about this leading to the O2
sensors; I'll be me not clipping this back onto the manifold bottom has
caused a short somewhere because that harness is just dangling in place.
Post by Jeff Strickland
You can safely drive this car while you are sorting it out.
The fuse involved is fuse&28, and I highly doubt the fuse is the
problem because according to the owners manual, that appears to be a
HEGO Sensor, Transmission Shift Solenoid, Canister Vent, A/C Clutch
Relay, Thermactor Bypass Solenoid
If the fuse was bad the tranny wouldn't shift very well either and
he'd be getting an evap code.
I do also get P1000 code, but I've had that ever since MIL reset 6
weeks ago. It did not fail inspection with this code.
I'll check that fuse later this morning just in case.
I can find very little, if any, change in terms of how it runs. I
know nobody wants to hear this as I really pushed the issue the last
time, but LTFT still run around +10. STFT do not and stay around 0.
I wish I knew for a fact where these sensors are located. I believe
when I had the manifold off a few weeks ago, one of them was
underneath the manifold between the engine and firewall. Not sure if
this was the upstream sensor or not. I don't have much luck finding
diagrams for the location and I'm also going to need a schematic I
would think to check the voltages if I need to.
Sam, you must connect the plug that is hanging free. Nothing else
matters until you plug everything back together. The O2 sensors are
mounted to the exhaust system before the CATs. Typically the sensor is
located where the manifold for 3 cylinders comes together. There is a
sensor on each bank of cylinders, and there is a sensor before the CAT
and after the CAT. The sensor before the CAT tells the computer to make
small adjustments to the fuel trim, the sensor after the CAT only
detects that what comes out of the CAT is cleaner than what went in.
Put your hand on the engine. Move your hand along the exhaust system
until you come to an electrical device/connection. This is the upstream
O2 Sensor -- it is before the CAT by the direction that the exhaust
flows. Continue to follow the exhaust system over the CAT to the next
electrical device/connection. This is the downstream O2 Sensor -- it is
after the CAT by the direction that the exhaust flows. Some cars can
have additional CATs, and there will be an O2 Sensor after any
additional CATs, but I'm pretty sure your Taurus does not have any
additional CATs, so the point is moot. I only mention it for the
possible educational value in telling you that some cars have more than
one CAT per exhaust bank.
The codes you are having, P0135 and P0155 tell you nothing about how
well the sensors work, or do not work, they only tell you that the
heater elements do not work. YOU told us they are not connected -- you
left a connector unplugged -- and the computer does not know unplugged
from blown fuse, so it is all the same to the computer.
Sorry to mislead, Jeff, but they are connected. What I was trying to
manifold. I did plug them back together when I did the spark plug job a
bottom of the manifold. So there is continuity, yes, I just didn't
reattach the socket/plug combo to the manifold via its clip. So it has
been this combo which has been dangling since I did the job. One of my
movement, that I now have an open or short in one of the wires. I plan
if one is blown, and reset the codes and see what happens.