1997 f355 spider,fab speed headers,cats and tubi. Always got the odd code, P1448, cats are good, bypass works fine. My yellow top battery got drained, so charged, restarted but after it went to open loop mode (pretty sure was just before fans kicked in) while idling in driveway, Got P1448 code and slow down light flashing. Checked and cleared code, shut down car, powered off for an hour, restarted and still flashing slow down on cold motor. Tried again today, started with a clean power off over night, started cold and flashing light still. Scanned and no pending codes with light flashing. Any ideas? Thermocouples tested good, new O2 sensors 3 weeks ago and ran fine until battery got drained down and this started. Car isn't on the road yet so been running I driveway, no road driving yet.
TCU is done. Swap from side to side and see if code moves. Very common problem. Likely original black potted unit.
Got it cleared and running top notch here. Thanks for the input MCJOE, as I mentioned, tcu's tested out perfectly, that's what had me baffled. Did a code clear while hitting fob after, thanks to tr512's call, but thanks again!
Mike, I owe you big time, you just have to answer the phone phone when I fly into to Van! Lmao Thanks again people, it's singing a nice tune here, thanks to everyone here with your input!
I initially cleared the P1448 with a blue tooth style reader, yet sdl still flashing., no codes showing. Hooked up with my regular corded reader, ignition key on, pressed fob to disable alarm , sdl flashing, read for codes again on scanner. No code came up, but noticed it showed 'pending code' in upper corner of scanner, pressed fob again and clear code on scanner (even though it showed no new codes) , sdl stopped flashing . Disconnected scanner and started car. It ran better then ever. So lesson learned, bluetooth type scanner was vague, showing basic information on codes, where hand held corded model was more descriptive showing a past pending code in there somewhere, I've had for months I guess, but gone now. It's the pressing of fob and hitting erase on scanner even though no code showing, erase anyway.
IMO. All of that has nothing to do with your sdl. All you did was successfully clear it. You didn't fix the issue. It will come back.
Well, whatever it was has been cleared, been there since last July I'm assuming, as car runs as smooth as it did before that. I've done a lot of things since then ie: new sensors etc etc and is running in sync finally. Will post update if/when anything pops up related in the future.
Just so you know , the 02 sensors have nothing to do with the SDL. Most likely you have an intermittent issue with a TC or the Cat ECUs.
Here's a great video showing how Thermocouples fail. This is exactly what I experienced with one of my TC that I was able to visualize while driving as the leads are tapped. You can't see this type of failure causing intermittency visually without a DVOM. This happens on our cars more than most realize. https://www.youtube.com/watch?v=cKzePbknqnU
Bob Their is more to the story..he made the SDL come on, had something to do with dead battery. He was having trouble clearing the SDL.I don't think he has a problem with a SDL it was man made...or should i say Ron made...lol
Thanks Mike, it was a weird scenario as Mike mentioned, it came on with a few bits of input, maybe read the start of the issue Bob. I started it and ran again today, ran flawless , no lights, revs clean as it should. A different scenario then most but it's what happened and is cured.
I am not trying to be argumentative but as far as this issue is concerned I don't think that anything you did resolved the issue and I don't think the issue was on account of any battery related incident. My understanding of the OBD protocol is that you cannot clear a pending code. You can clear the light but the pending code will remain until 30-40 drive cycles or such and if the issue doesn't reappear, it will go away. The lights and CELs are annoying but they tell a story as to what is going on.
Bob, when you clear the codes the pending code are cleared too. The drive cycle thing is that a pending code will be erased automatically after XX drive cycles if the fault is not detected again. Not that anyone cares.
I mispoke on the pending code issue. I was referring to the underlying issue not being resolved and reappearing. My mistake. Mike will you explain how using a fob sequence aids in clearing OBD issues?
Bob When you try to read your codes or clear them you must hit your fob first.You only have so much time before the alarm sets again, i think like 3min.Then their was a second problem the scanner he was using.Ron can explain that one. All i helped him with was how to get rid of the SDL and pending code.
I have no idea what you're referring to with the immobilizer (fob). I have cleared them with the engine running ( no fob intervention ) . I hope his sdl issue was a one off thing for him.
Let your car sit for 5min ,Try clearing them or even reading them without pressing your fob first if your motor is off, key forward.. Yes you can clear codes with the engine running...but sometimes it won't clear pending codes depending on scanner.I find it's best to clear all codes and pending with alarm and motor off key forward. Like i said his SDL was man made, and he couldn't clear it.. along with his pending codes since july.Clear your codes however you like...and what works for you.
Many obd readers will only read one of the ecus if the immobilizer is not deactivated by pressing the button. Therefore a code on the other unread ecu will not be read or clear.
That's EXACTLY what has happened in my case. I used a wired reader to obd2 before, then bought a bluetooth unit. The bluetooth did the basics on the run to clear a code, but never showed anything pending. Using the hard wired unit and Mikes instructions, it also showed a pending code that had been there for months, since I bought the bluetooth unit. I followed his instructions and after the pending code was cleared, fired up car and it ran like a dream. It ran great before that one day in July, always had a slight stutter at takeoffs or stoplights, it's smooth now. Also note as I mentioned, I've changed sensors and plug wires last month, and car seems like it's in sync again, smooth and snappy.
