ISSUE Solved!!!! 1994 z28 dtc codes can someone tell me what it might be?
07-21-2013, 07:02 PM
#1
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ISSUE Solved!!!! 1994 z28 dtc codes can someone tell me what it might be? i have a 1994 camaro z28 and just borrowed a scanner from a buddy and i have scanned and got these codes can anyone make sense of what the main problem might be?
dtc 42,43,44,45,51,53,54,55
swapped pcm and alternator and battery in good shape can it be optispark related? maybe shorted out or ICM
thanks everyone
dtc 42,43,44,45,51,53,54,55
swapped pcm and alternator and battery in good shape can it be optispark related? maybe shorted out or ICM
thanks everyone
Last edited by 95_Z-28_runner; 08-06-2013 at 11:24 PM.
07-21-2013, 07:24 PM
#2
42 PCM did not detect any EST signal within 84 crankshaft revolutions.
43 One or both of the knock sensors were either open or grounded for 5 seconds.
44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation.
45 Left oxygen sensor voltage was over 0.7 volts for 50 seconds when the throttle angle was above 4% during closed loop operation.
51 PROM error.
53 ECM detected a battery voltage either above 17.1 volts.
55 ECM detected a lean oxygen sensor voltage for 3 seconds during the power enrichment modes of operation.
Another Link from Rob's site.
http://shbox.com/1/Dtcs.htm
43 One or both of the knock sensors were either open or grounded for 5 seconds.
44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation.
45 Left oxygen sensor voltage was over 0.7 volts for 50 seconds when the throttle angle was above 4% during closed loop operation.
51 PROM error.
53 ECM detected a battery voltage either above 17.1 volts.
55 ECM detected a lean oxygen sensor voltage for 3 seconds during the power enrichment modes of operation.
Another Link from Rob's site.
http://shbox.com/1/Dtcs.htm
07-21-2013, 07:34 PM
#3
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All the crazy voltage readings on every code it seems pretty likely the alternator being the culprit. Also check all your grounds and your o2 wires didn't get cooked
07-24-2013, 01:14 AM
#5
I had a charging problem and took the alternator into an auto parts store for them to test it. Their machine gave it the OK but I replaced it anyway because I absolutely could not think of what else it might be. The new alternator fixed the problem. If you're alternator isn't 100%, just replace it anyway.
07-24-2013, 01:35 AM
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yea i thought as much i had mine tested too. i bet the machines just test if its putting volts out and not anything else. i will hook that alternator back up to run it and reset codes and take the power feed off the alternator and if no lights come on that must be the problem. do you think the theory of that test is worth trying?
07-25-2013, 04:28 PM
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ok just tested the alternator and battery with a multimeter and my power probe and checks out and all the grounds under the hood including junction boxes. checked all fuses and some of them were giving a pulse reading even the fuses on the interior. so i don't know what the deal is with all the codes going off in my pcm fried but it cannot because it starts and runs but crappy with burning rich. has fuel pressure and fuel pump cycles on and off during the key being on.
anyone with other ideas you help would be great
anyone with other ideas you help would be great
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07-27-2013, 12:58 AM
#8
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I have a 94 z28 and it was running fine last week then one night i went out to go for a drive and started it and it was running so rough. I disconnected the battery for 30 seconds reconnected and she started and ran good.
Next day i go out to start and its trying to crank over but won't start unless i tap my foot on the gas pedal a few times, but even when it starts once it gets warm it starts to run a lil rough.
I scanned my car and got the same codes as you 42,43,44,45,51,53,54,55
I kinda suspect the opti is bad, my o2's could probably use a change and the alternator could possibly be bad too, I'm not really sure where to start...
Next day i go out to start and its trying to crank over but won't start unless i tap my foot on the gas pedal a few times, but even when it starts once it gets warm it starts to run a lil rough.
I scanned my car and got the same codes as you 42,43,44,45,51,53,54,55
I kinda suspect the opti is bad, my o2's could probably use a change and the alternator could possibly be bad too, I'm not really sure where to start...
07-27-2013, 02:14 PM
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im in the same boat the alternator tested fine when i hooked my muiltmeter up as well as the battery getting a good charge. i used my power probe 3 and checked every ground under and in the engine bay and all power leads and everything is good. so im still a little confused unless the pcm is fried but if that was the case i would not be running and driving even though idle is rough it smooths out on acceration. so i don't know any help anyone has would be great. if it is infect the opti not a problem but don't want to tear it down if i don't have to because then i will have to do a full service tune up, water pump and a few other things. plus 54 DTC should not be on there and is a y body code from what people have told me. so i don't know
07-27-2013, 09:08 PM
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they came in the Y body PCMs but just to let people know i tested all the PCM pig tails with my power probe 3 and red,blk,blue, and clear all were good and no breaks in the circuity on that end and all the grounds and power supplies were good, so i think the culprit here is the PCM it self i think its not throwing the correct voltage out to all the sensors and causing current spikes and lows. causing all the codes. or it might be an y body computer all together. so any suggestions or commits on my reasoning let me know. i can all way appreciate many other brains than just mine.
07-27-2013, 11:48 PM
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i have a few camaros and i just swapped PCM off my daily driver that has no codes.
plugged it in and did the same thing with the same codes. im about ready to disassemble the wiring in the whole car lol are all of the codes related to the same B+ supply in wiring somewhere? anyone help?
plugged it in and did the same thing with the same codes. im about ready to disassemble the wiring in the whole car lol are all of the codes related to the same B+ supply in wiring somewhere? anyone help?
07-28-2013, 03:28 PM
#15
I'm sure you've thought of this but what about putting some of your parts-in-question (alternator, ignition components etc) into any of your Camaros that are running fine?
When you clear the codes, which ones come back?
Did you measure amps?
There could also be AC volts leaking into the system wreaking havoc.
How do your "big 3" wires look? Alt-bat, bat-block, block-chassis? Everything nice n' tight?
When you clear the codes, which ones come back?
Did you measure amps?
There could also be AC volts leaking into the system wreaking havoc.
How do your "big 3" wires look? Alt-bat, bat-block, block-chassis? Everything nice n' tight?
07-28-2013, 04:11 PM
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Well could an alternator be bad even if it was charging the battery at the right voltage? And I was thinking about taking the icm and coil assembly out of my other car that functions and swapping them. At least I know the PCM is
not bad. When I clear codes all of them come right back within a few sec of just turning on the ignition with engine off. One time while turning the key fast the scanner did not pick up any codes but that was the only time. And the big three where corroded and not good so I re crimped and now are all clean. Where do you think the ac volts leak
could be? And have not checked ac current on components yet but will later when it cools down
not bad. When I clear codes all of them come right back within a few sec of just turning on the ignition with engine off. One time while turning the key fast the scanner did not pick up any codes but that was the only time. And the big three where corroded and not good so I re crimped and now are all clean. Where do you think the ac volts leak
could be? And have not checked ac current on components yet but will later when it cools down
07-29-2013, 12:24 AM
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yea im starting to think so because that and the battery is the only power directed to the pcm. is there any other voltage regulator that im missing for the pcm? or any common wires that get broken?
