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OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W


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rossman21
Novice

Oct 7, 2016, 5:57 AM

Post #1 of 8 (7068 views)
OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

I have a 1994 Chevy Astro 4.3L VIN W (CMFI) and I am get an OBD1 Trouble Code of 35 and 82.
In looking up these trouble codes, it seems 35 deals with the Idle Air Control (IAC) and 82 is the Crankshaft Position sensor.
I have just replaced the Idle Air Control (IAC) and reset the codes (disconnected the battery for 30 seconds). Both codes reappear. My next thought is to replace the Crankshaft Position sensor, but in 1994, there is no such sensor (that did not begin until 1995) - any suggestions?


kev2
Veteran
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Oct 7, 2016, 6:18 AM

Post #2 of 8 (7059 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

what issues are you having?
I show 82 as a transmission code, 'shift solenoid circuit'


Discretesignals
Ultimate Carjunky / Moderator
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Oct 7, 2016, 9:12 AM

Post #3 of 8 (7048 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

Does this engine have high or low idle speed problems, stalling, or is running rough? Kevin asked a good question.


Code 35 doesn't necessary mean the IAC motor itself is the culprit. It just means the PCM is unable to control the idle speed properly or there is another issue that is affecting the engine speed at idle that the PCM can't control with the IAC motor. It is also possible that there can be IAC circuit issues, but you need a scan tool with bidirectional control and an IAC tester to test those circuits. You can use an oscilloscope to see how the PCM is driving the IAC motor also.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Oct 7, 2016, 9:17 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 7, 2016, 9:45 AM

Post #4 of 8 (7040 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

IKD - Old trust paper book on these codes. 35 - can't control idle basically already said by DS. 82 just meant it can't communicate my book said (Saturn) as if only that maker installed that but don't believe it. IDK - is plug all messed up?


If not already said, check hard for vacuum leaks and anything to do with incoming air. Old enough to crack, holes - who knows? They will not run right (about anything) if vacuum and air flow isn't in control. Unmeter air would alter idle out of its ability to self adjust it within norms,


T



kev2
Veteran
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Oct 7, 2016, 10:24 AM

Post #5 of 8 (7035 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

code 82 is coming up as a trans code. 93-95 4.3L VIN W

82


1-2 Shift Solenoid Circuit Fault
How is engine idle speed - correct and stable ? High. low or hunting?
How is trans shifting? Is it stuck in one gear (3rd) so called limp mode ?


rossman21
Novice

Oct 8, 2016, 6:07 PM

Post #6 of 8 (7016 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

No issues with the transmission. Shifts fine.


rossman21
Novice

Oct 8, 2016, 6:10 PM

Post #7 of 8 (7016 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

Engine seams to run a high idle - but not all the time. When slowing down it seems the Idle is high - it takes a little longer than it should (a second or two) and then the Idle corrects itself.
It idles fine in Park or when stopped at a light.


rossman21
Novice

Oct 8, 2016, 6:13 PM

Post #8 of 8 (7014 views)
Re: OBD1 code 35 and code 82 - 1994 Chevy Astro 4.3l W Sign In

When slowing down, it seems to idle high - is this the 3rd gear limp mode?
What can I do about it?






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