HELP -- OBDII / Drive Cycle Nightmare!

[Servekaos]

Hey guys, I've been having a serious issue for a while and I need to find a way to remedy it in the next two days to renew my CT registration.

I initially failed my emissions tests for a misfire code that was addressed. Basically, my O2 sensors were lazy and it was causing an intermittent misfire. This was causing the O2 sensor and a few other sensors to set as "inc" during the drive cycle tests.

The repairs have been completed to the satisfaction of OBDII going as far as to set all but one of the monitors (catalyst monitor) to "OK." I've done the complete Ford driving cycle several times and each time the result is the same. Each monitor will set within about 10 minutes of driving, except the catalyst monitor.

The problem is that, though OBDII recognizes the monitors have been set, each time the truck is shut off for any period of time the readiness monitors are cleared out again. Thus, I have tried to pass the emissions test something like nine times, each time the result being an aborted test due to the readiness monitors. It's very, very frustrating because I know I should be able to pass but now there's this.

I've heard that weak batteries can cause this issue but the battery is new as of last season. No corrosion on the terminals or cables that I can see. Also, my clock on my radio doesn't lose time or any of my settings so I don't think voltage is dropping too low. Also I've been told to check my fuses but none of them seem to be bad. I don't have any aftermarket alarms installed but there is some type of towing accessory that I've never used that isn't from the factory. The wiring for that sits directly below the steering column so I was able to eyeball it and it doesn't look faulty at all. This was installed when I bought the truck and did not cause it to fail emissions last time.

In case it's helpful, here's a short list of major parts I've replaced in the past year: 6x spark plugs, 6x wires, fuel filter, coil pack, FelPro upper intake manifold gaskets, new OEM O2 sensors (all three), new battery, new thermostat, misc. other parts.

tl;dr: The drive cycle monitors on my truck keep resetting every time the truck is shut off for no apparent reason...gotta pass emissions tomorrow! HELP!! lol

 

[Servekaos]

Bump. Anyone?

 

[enjr44]

Well, tomorrow has come and gone and no answer, so I will jump.

I will be the first to tell you I do not have definitive answer for you. Having said that, there is only one way the computer ram will reset and lose data (unless the ram itself is bad) . That is no power to ram when vehicle is off (bad wire or fuse, bad ground or internal open in the ECU). My guess is the ram is ok since the drive cycle will work (set); but, once you turn it off the ECU loses the data.

I guess I would go to the tech section and go thru the wiring diagrams in great detail. My guess is that you broke/disconnected/shorted something while doing some other work. I mean it was not always this way, so you have to go back to where it was before it is the way it is. Had an old time mentor always said, if something don't work the way it should after you worked on it (or worked on something else), you broke it, so go back and unfix it.

 

[kimcrwbr1]

Pull all the connectors apart and clean with elecrical cleaner and put back together with dielectric grease including the large connector on the ECM. Look close for any pins not all the way into position. Look close for any bare cracked or broken wires and fix as necessary. Especially around the exhaust manifolds. It is probably something simple that you have overlooked.

 

[adsm08]

Check pin 55 at the PCM for power key off. That's the power for the memory.

Also if you can view live data while driving compare the signals from the upstream and downstream sensors. Best viewed as a graph. If the downstream graph looks like the upstream your cats are shot. That could keep you from completing the cat monitor.

 

[BRUTUS_T_HOG]

Check fuse 6 10A in the underhood fuse box. If that is good you will need to check power at PCM pin 55. If good the PCM is possibly bad.

Does your code reader have access to mode $06 data? Any pending codes?

I think if your monitors are truly resetting you will never get it to pass.

 

[Servekaos]

Thanks for the suggestions guys. Sorry for the delay in replies, the issue is still ongoing. I'm not so concerned about the catalyst/EVAP monitors setting because I can still pass with 2 "not ready." According to my records, the last time I passed emissions those two weren't ready either. The real problem is that my Actron will literally show all but one set to "OK" after some driving. Which is great. Bs soon as the truck is shut off the scanner will go back to 4 "not ready." It's endlessly frustrating...it's as though the test results aren't being stored in the KAM and I'm just wasting time and gas. I've visually inspected every wire I can find without ripping things apart, everything seems intact and in good shape.

I'll check the #6 fuse again, I checked all the fuses last week and they were all good but it can't hurt to recheck them...also going to try to check my alternator output, is it possible a slightly weak alternator could be a culprit? I don't seem to have any charging issues/pulsing lights/weak lights under load, etc.

What's the best way to go about checking power at pin 55? I know it's hard to know without proper diagnosis but I have a hard time believing the PCM could have gone bad. But then again, who knows...I'm just trying to soak up as much info about this as possible.

 

[huh?]

1: remove negative battery cable from battery,

2: remove connector from the control module,

3: reattach negative battery cable to battery,

4: with the ignition switch in the "off" position check pin 55 for voltage.

5: repeat step 1,

6: reattach connector to the control module,

7: repeat step 3.

if you don't get any voltage reading in step 4, can we get you to check with the key in the other positions.

it may be faster to sever the wire from pin 55 and splice on a wire long enough to reach the positive battery terminal. include the appropriate circuit protection(10 amp fuse?), and use the same or thicker gauge of wire.

 

[Servekaos]

Okay, so today after some driving I was able to get ALL of the monitors to set, catalyst included, which to my knowledge has never set itself to OK. If I shut the truck off for ten seconds and restart the monitors will all stay OK. If I leave it sitting for 5 minutes and restart it they will all revert back to INC. So it has to be some kind of power issue.

This may sound stupid but the PCM is below the steering column, right? How can I identify pin 55 and test it? Will a test light work?

I'm at the DMV picking up a temporary registration...again...that will buy me a little more time. Will update later today as I have more time to look into this.

 

[Servekaos]

Okay so I figured out where the PCM connector is and detached it (bolt was rounded, what a bitch to get off) with the negative battery cable off.

You might have guessed but I'm a newb with a multimeter but I do have one. What voltages will I be looking for on pin 55?

 

[enjr44]

12 volts all the time with the key out or for that matter with the key in any position. Any time the battery is connected.

I would think that you would be losing the radio preset stations, too. When you have the battery replaced at a shop they usually put an adapter into the cigar lighter socket to keep the old data from being lost.

 

[Servekaos]

No loss of radio presets, clock, anything...it's very strange.

Any tips on how to check the voltages? I tried last night -- I stuck one tip from the multimeter into the header where pin 55 should go and the other to ground. No voltage reading. I don't know if the tip of the meter was making contact or not since the hole is so small. Should I be checking the pin itself or the plug the pin connects to?

 

[enjr44]

To check voltage at pin 55 you put the positive meter lead on the connector's pin 55 and the negative lead to a good ground with the battery connected. You may have to put a small wire into the PCM connector if your meter lead is too large to fit into the hole in the connector. You should get 12 volts (or battery voltage). Set the meter to a DC range that is above 12 volts; but, as close to it as the meter allows.

Don't force it or you can damage it. I use spare pins like are on the PCM; but, if you don't have one of those use a small wire.

If you don't have voltage then you have found the problem. It is a break (bad fuse or wire) between that pin and the battery. I don't think it is a bad ground or you would have other problems too.

 

[enjr44]

Double post.

 

[enjr44]

You are a GI, right? IF you are still having problems checking it, get one of the guys from one of the base/post electrical maintenance shops to give you a hand or take it to the auto hobby shop and get some help.