I cleaned all of the gunk off of everything with a dry paper towel and q-tips (I know it would be best if I had throttle body cleaner…). I then drove around a few miles at low speeds and everything seemed perfect, for the first time all week. Of course, I need to do some highway driving to confirm.
From just those couple miles to pending codes, P0135 and P0155 cropped up. Seems to me that P0455 is usually slower to pop up, but I could be wrong. I’ll do more driving tomorrow and continue researching.
For what it’s worth: I drove the car for maybe 10 miles, got up to 45mph. The shifting problem did not arise at all, the car felt perfect. Still too early to be reassured, but whatever. P0135 and P0155 popped up as stored codes.
I might have found the problem for real this time!
Remember, when I was asked by hellokit to check the heater grounds? And I searched for them but bitched about how there were soooo many wires and I couldn’t possibly follow them all? Yeah, that was pathetic. Just now I decided to scrub all of the grounds that are screwed into the chassis with a wire brush and some diet coke (I’ll put contact cleaner on them when I find it). Anyways, in doing so, I just happened to find the screw that screws down the white and black wires (along with a braided cable looking thing and 2 black wires) RIGHT next to the PCM. Unlike the other screws, this one is painted green to connote importance, no doubt. That whole assembly did not look good… It is right underneath the cabin air intake and the entire assembly was very, very dusty. So I unscrewed it all, scrubbed it with the wire brush, rinsed it with diet coke, and put it back. I’ll test it tonight or tomorrow.
Maybe this is it? Maybe this would account for the 0ohm readings that I last got for the heater pins?
To recap: P0135 and P0155 means that there is a problem in the left, and right, front oxygen sensor heaters/circuits. The problem could be, the voltage, or current, aren’t correct, since, the PCM has detection circuitry for both. So, tests have to be done to get more specific data. mfaerber has attempted to make some of those tests, with uncertain results.
P0455 is code for: “A gross leak, OR, no flow has been detected in the [fuel] evaporative control system.” It is not the code for the gas cap leaking “fumes”. Code P0457 is for that.
Rather than restate tests given in repair sources, I refer mfaerber to one, such as alldata, or, a qualified repair shop.
Anyone with ideas?
On my scan tool, after it says P0455, it says “large leak.” Interestingly, the online Chilton’s repair manual does not list P0455 for my car… I will taking a test drive to pick up some things at advance auto parts in a few minutes, will post results.
Drove maybe 3 miles and the CEL came on after about the first (very usual, it usually takes 20 miles). During that drive the car was not shifting too great, but that could be symptomatic of what it normally does when the battery/PCM is disconnected. Erased the codes (P0135 & P0155). Parked the car for about a half hour. Drove home about 3 miles.
CEL did not come back on, but there are pending codes and freeze frame data:
Pending Codes:
P0708 Transmission Range Sensor A Circuit High
P0135 O2 Sensor Heater Circuit Bank 1 Sensor 1
P0155 O2 Sensor Heater Circuit Bank 2 Sensor 1
I’ve never had P0708, I’m going to research it now, but maybe it’s a result of me monkeying around with stuff today? One of the things I did for the first time was remove the EGR to make sure it wasn’t blocked up. It had a thin layer of black powder in it, but no blockage.
AND
When I was sitting in my driveway, with the car running, at the end of my trips, the OD Off light started flashing. I pressed the OD button repeatedly, to no effect. The OD light has flashed in the past, I have neglected to mention that because it is rare.
You don’t seem to understand the results of resistance test on the PCM pins I had you do Matthew. If you did it correctly, and I assume you did, you proved that there is a problem INSIDE the PCM because of the different results you got on the pins. There were no outside connections to it, or should have been at least. The heater codes are not going to go away until you replace the PCM. The P0708 code you now have is probably due to something you did while working on the engine and have disconnected a connector somewhere.
You’re right about the understanding part… And I hope you are right because I really want to be done with all of this… I will probably buy a new PCM tomorrow…
Let me ask you this, does it matter that when I tested the PCM’s pins, I had one probe on a pin, and the other on a grounding point. When I say “grounding point”, I mean a nearby spot on the car’s chassis where are there some black wires bolted to the chassis. I think that is what you wanted before, HOWEVER, does it matter that that grounding point was NOT the the grounding point RIGHT next to the PCM, the one with the green bolt that I now think is directly associated with the O2 heater wires?
Also, after much reading, I’m suspicious that my shifting problem (P0708) might be a result of a failing DPFE sensor… The hoses going to it are fine, but I’ve never taken it apart.
I don’t see anything amiss in the freeze frame data.
GROUND: a ground is any part of the car body, transmission body, or engine body. The negative probe of the multimeter, when checking the ground from the PCM, could be touched anywhere on any of those bodys.
Because rust passes very little voltage (high ohms), when taking a multimeter reading on any of the bodys, scratch the surface until you hit shiny metal with the probe tip.
0 ohms means there is no resistance to ground…current can pass to ground without hindrance (without ohms). This is what you want for a circuit to ground (after it’s powered its load).
Whenever a code says something about INPUT being high/low/none, the reference is to inputto the PCM (engine computer). And the input is voltage or current.
Yes, whenever I have touched a probe lead to ground, I always make sure the ground clean (and whispers I spit on it for good measure… hey, it’s my car, don’t judge me).
I cleared the codes via the scan tool before I set off to work, which includes city and highway driving for about 15 miles. The shifting problem (i.e. does not shift when it should; seems to slip out of gear randomly as well) remained. The CEL did NOT come on, but it usually does not until the trip home. Two pending codes, P0135 and P0155. Interestingly, P0708 did NOT come on. More interestingly, NO freeze frame data was recorded.
When a problem is PENDING (persists) long enough, the engine computer turns on the “check engine light”. When that happens, the freeze frame data sets. Freeze frame data is some of the conditions that existed when the CES set. It shows stuff like engine coolant temperature, fuel flow into the engine, vehicle speed, engine rpm, whether the engine computer is running in ‘closed loop’ (running on sensor (etc.) inputs, or, not.
The code P0708 is for input (high voltage or current) to the engine computer from the Transmission Range Selector switch. To troubleshoot it, you need the alldata charts. They are available from your public library, or from your online subscription ($25 year).
At your public library computer, go to Electronic Data Base > Reference > alldata > Vehicle Level > Powertrain Management > Computers and Control Systems > Testing and Inspection > Pinpoint Tests > choose which set of charts and DTC Codes. Download and print whichever pertain.
EDIT
Oh, and the 2 pending codes, 135 and 155, of course became real codes. No other codes exist. Which means that i have not seen my friend P0455 for a couple days now…
But, it turns out I forgot to turn key to RUN. So, my results are worthless and I’ll have to do it again tomorrow…
Anyways, I found a couple cracks in a very short bit of rubber tubing attached to the underneath of the throttle body and attaching to a metal tube that I think extends to the firewall (could be wrong, it is long). I taped it up for now…
I also removed the EGR valve and throttle body and cleaned them with Carb Cleaner/Throttle Body Cleaner. There were not any blockages and the EGR seems to open/close/hold suction just fine.
Ran the car in the driveway for about 5 minutes, reved it once up to 3k. Before I reved it the OD light was flashing… By the time I turned the car off it was no longer flashing. The scan tool recorded two pending codes that I have never had before:
P0122 Throttle / Pedal Position Sensor / Switch A Circuit Low
P0760 Shift Solenoid C
Maybe, like with P0708, it’s just something temporary because I was monkeying around with things… I’ll clear the codes tomorrow before driving and update.
You’ve removed the PCM (engine computer, yet? The PCM oxygen sensor heater internal circuits can be tested by following the procedure given to the post: Oxygen Sensor Codes P0135, P0141, P0155. Just click Search, at the top of the page, and type that post name in the Keywords block.
We breathlessly await further missives of events, from you, as they unfold.
Oh yes, I have removed the PCM and took apart its’ casing to visually inspect the circuit board. Everything looked really good and clean. I think I understand what you and Cougar wrote as of the time of this post, but it sounds like what I have already done the last couple times you all gave me tests to do.
Cleared the codes this morning. After my drive to work there were 3 pending codes: P0135, P0155 and P0455.
On a side note, I’m going to test the TPS tonight to see if it is OK, as it may be contributing to my shifting problem.
Hey Matthew, The O2 sensors are a red herring. The real problem is the Mass Air. The O2 sensors are scheduled to be replaced at 100k and may provide better fuel economy. They tend to get sluggish with age and mileage. I don’t know where in NC you are but I own North Hills Automotive, in Greenville, SC. You can check us out at www.northhillsauto.com. I also do a weekly radio show here in Greenville on AM 660, The Drivingline. Iv’e seen this FORD problem many times and feel pretty confident that the Mass Air will fix you up. If you need more info you can call my show Saturday between 8 and 10 am. I also have a fellow on staff who is our director of training that has a lot more knowkledge than I do. I’d be happy to run this past him. He was the 2002 North American ASE technician of the year. Good Luck, Ken Gamble, Greenville SC
Just wondering if you think it is time to go to the dealership to have the car checked. Probably there is another service bulletin or something that could help your problem once and for all. (I know it sounds expensive, but maybe you have spent the same amount of money already)
When you check the tps (throttle position sensor), you can look at its voltage graph on your scan tool screen, or use your multimeter to look at the electrical resistance (ohms). This article tells you more. Look at “Problem #4”. The tps graph is Fig. 6 (not, Fig.7). http://www.autotap.com/DIY_booklet.html#prob4
Voltage spikes on the tps response, especially at idle, and just off idle, would cause your PCM (engine computer) to go nuts whenever the throttle (gas pedal) is moved. Move the throttle slowly, and watch for voltage spikes (or, if using the multimeter, the ohms being erratic).
Here is another source of information for testing the tps (which you may already have).
There is a bonus! You can enlarge all those pretty graphs, download and print them for reference.