TCCoA Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
956 Posts
Discussion Starter #1
I have a '97 4.6L with the following codes. With all of these codes at one time, is it something obvious? Any ideas? The car will act like its going to stall every once in a while. I'll give it gas and it doesn't want to go.

P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
P0136 O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P1131 Lack Of HO2S11 Switches - Sensor Indicates Lean
P1151 Lack Of HO2S21 Switches - Sensor Indicates Lean
 

·
Registered
Joined
·
139 Posts
Hello,
With the lean condition it could be many things. Four of the codes you have listed above really are related to the lean issue. What I remember from the Ford program at UTI is that it could be fuel related. A junk fuel pump could be one of the reasons, a clogged fuel filter would be another maybe even the fuel pressure regulator could be going south of cheese. But if it was the things I listed above I would imagine you would get more codes including similar codes on bank 2. Something else you could look into would be a vacuum leak on bank one, I think it is the pass side but I could be wrong, this would also cause a lean condition. The simplest way that I find vacuum leaks is with a propane cylinder. Obviously don't light it and just sweep it around the engine, if it is a leak the idle speed will come up. Although I do not know about the first few codes but you could always check the wiring because you never know what could have happened.

Nick
 

·
Registered
Joined
·
150 Posts
I have the same codes after replacing the o2's on bank 1. I initially only had a Bank 1 US malfunction so I replaced both and got all the other codes for my trouble. I am in the process of checking the MAP sensor (Tachometer wired to signal and ground to check the frequency since I don't have an osciloscope). I admit jerking the harness around is a possible problem but it all started when I replaced the intake gaskets and changed the AMP with a used one I picked up at the boneyard. I have cleaned the MAF, new plugs, new Fuel filter and the most luck I've had yet was a tank full of Chevron gas. It idles fine most of the time but shortly after placing in park it starts to stumble etc.

my 0.02
 

·
Registered
Joined
·
171 Posts
try this...check the 2 plugs beside the tailshaft of the trans. The wires will be going up into the floor of the car and will have a ruber boot on them at the floor. Where the wires exit and enter the plugs, if you have any kind of oil leak, will melt together and will cause all kinds of trouble including but not limited to sloppy or missed shifts, hard shifts, no shifts, no speedometer or the speedo needle bouncing all over the place, no reverse lights, no turn signals (but you will have hazards), check engine codes relating to no vss input, no or wrong mlps input, wrong, slow, lean or rich o2 input (on any and or all banks), o2 heater malfunction (again on any and all banks), poor engine performance, decreased fuel economy, no or irregular torque converter lockup, blown fuses in both the dash and underhood fuse panels, and a few other things I am probably missing. You can fix this 3 ways. First is to remove the harness from the trans and pull out the wire, pin by pin and put heat shrink on them (this will only work if the car side of the harness still has good insulation on the wires). Second is to remove the wires pin by pin and heatshrink them on both sides of the plug (its a MAJOR PITA but doable) or third like I did and it is still a pain but not so bad is to cut the plug out and remove the damaged wire. Then using the butt splices that you have to heat up to seal, butt splice them back together. This method requires you to remove the harness from the trans and o2 sensors but then go to a bench or some other work table and remove the damaged wire and install the splices on the wires. Then you get to crawl under the car and match color for color and crimp them on. A little heat shrink and you are back in business. I have had to do this to my cougar and my m8
 

·
Super Moderator
Joined
·
7,565 Posts
When it starts "running like crap" is it misfiring? An intermittent misfire will often set a code for O2S lean before it will actually set a misfire code. That would explain P0131, P1131, and P1151. This leaves 2 codes for B1S2, which will not have any effect on the way the car runs. You should replace that O2 sensor (unless it turns out its just unplugged), but first solve your running rough problem. I say use a scan tool to look at the freeze frame data for P1131 and P1151, and see if anything looks off. I'll bet those 2 codes occurred at the same time. If all the data looks normal, then look for maybe a vacuum leak, fouled plugs, an arcing plug wire, or something like that.
 

·
Registered
Joined
·
171 Posts
The transmission harness has nothing to do with the front oxygen sensors, which is what is being discussed here.
Tsk, Tsk, Tsk young grasshopper...you have much to learn about these Ford Motor Company diamonds in the rough. You see Circuit #359 is the ground for ALL of the oxygen sensors. Circuit #361 is power for ALL of the O2 sensors. BOTH OF THESE CIRCUITS PASS THROUGH AT LEAST ONE OF THESE CONNECTORS!!!!!! Now I have seen first hand what happens if these wires in the 2 connectors by the tailshaft get oil soaked for any length of time. The insulation turns to goo and the wires can short to each other which could be ground, +12vdc, 5+vdc or anywhere between including AC voltage. You may have a +12vcc wire that is shorted to the ground of a shift solenoid, or maybe a shift solenoid wire (the one that actually completes the circuit and starts the shift). There could be a partial short that results in the lowering of VCC to the EEC or CCRM which as most know our cars do some weird things with low voltage. With the wind lowing this harness just a bit the short can end up being continous or just whenever it feels like it or with the torque of the engine tugging or wiggling this harness and cause it to short if it's in bad enough condition. Short to an output on one of the O2 sensors. True this particular instance will not have nothing to do with the front O2 sensors. HOWEVER if it shorts out on either circuit 361 (which is +12vdc to a host of other stuff as well as the o2 sensors) OR circuit 359 which is the sensor GROUND and it can and will cause ill effects on the o2 sensors readings which in turn is VERY POSSIBLE given the age and conditions these wires are exposed. I am not saying, implying, preaching, or otherwise calling this problem's cause to be the the 2 aforementioned connectors or wires. You haven't done too much homework on the subject at hand, that's easy to tell. I have and figured that this small 2 minute inspection MAY save someone countless hours of parts swapping, troubleshooting and possible aggrivation. ALWAYS check the small stuff first. The small things will ALWAYS bite you in the rear, esp on these cars. Now that that's out of the way, I am sorry if I offended anyone. I know I am extremely grouchy and am on day 3 of a bad sinus infection.
 
1 - 14 of 14 Posts
Top