# '85 Z31 ECU trouble code 23



## Lynx88 (Feb 7, 2005)

Hey guys im new here but I am on my second z. I've got a '85 300zx non-turbo throwing code 23 and 31. I know 31 is for the A/C but will this shouldn't hurt smog right? Now code 23 is for the idle position switch correct? I tested the switch and it seems to work fine. Is there anything else under this code? And what pin on which connector to the ECU is connected to the TPS?
Thanks


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## Zen31ZR (Mar 24, 2004)

Go to Carfiche.com and download a factory service manual. All of the answers to your questions are in there.


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## 513KOE (May 15, 2008)

Hey, i was just wanderin, i have the same z as you, 1985 300zx z31 non turbo. in the boot on your right you have your spare tyre, behind this is a little metal box, it has 2 switches and 2 knobs and says Niles japan on it. nobody else can but can u please explain to me what this is??? thanx.


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## trever hill (May 25, 2009)

yeah i have the same car too, what are these two switches for?


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## BlindApple (Feb 12, 2010)

*Switches behind the spare tire*

This is the calibration for the in-dash compass


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## jamestiff2008 (Mar 21, 2010)

code 31 can mean many thing actually, computer, or load control... im having the exact same problem, did you ever figur anything out?


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## xxVERITASxx (Sep 13, 2009)

*Engine won't start! Showing ECU codes 23 & 31*

Hey guys, my '86 NA 300zx will not start. It just installed a new starter and the car at least sounds like it's trying, but the engine will not crank over. Pulled out the ECU and ran the self diagnostic test and it's showing codes 23 & 31. My AC does not work so I'm assuming that's code 31. What would keep the engine from cranking over? Please help!!!


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## brandomp (Aug 13, 2014)

*1985 300zx non-turbo error code 23 fix*

1985 Nissan 300zx non-turbo--The error code 23 refers to the idle/switch-TVS throttle valve sensor being defective or a wiring connection problem to the TVS. The car will run up to 2000rpm and then kick into "fail safe mode" which cuts off the fuel supply. If you wait a few seconds the engine will then come back to life as it gets more fuel, but will again kick into fail-safe mode as you give it more throttle.. I first replaced the TVS , however that didn't fix the problem. After a lot of wiring/testing I found that the electrical connector to the TVS was corroded internally. I replaced the electrical connector $16 and the problem is now fixed. I bought the connector from an Auto parts store (they had it in stock) so the connector may be somewhat standard across many models/car makes ? I don't deal with Nissan dealers anymore --they are the worst. The code 31 will go off if you apply a load on the system such as A/C or heat.


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## BeyondBiscuits2 (Jan 18, 2006)

xxVERITASxx said:


> Hey guys, my '86 NA 300zx will not start. It just installed a new starter and the car at least sounds like it's trying, but the engine will not crank over. Pulled out the ECU and ran the self diagnostic test and it's showing codes 23 & 31. My AC does not work so I'm assuming that's code 31. What would keep the engine from cranking over? Please help!!!


The only thing I know on the Z31s that will prevent your engine from cranking over is a security system issue, as the Z31 factory security system prevents the starter from cranking if tripped. That, or your engine is locked up. Or, did you mean it "cranks" but won't "run"?


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