# Trouble Codes



## Lynx88 (Feb 7, 2005)

Ok I ran the self-diagnosis on my 85' 300Zx Turbo today, and it gave me 5 codes. I have money to fix any problems, but I am not sure what the problem is. Here are the codes:

11
12
21
23
41

I can guess on what some of them mean but I just want a second opinion. All help is welcome.


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## Zen31ZR (Mar 24, 2004)

The Factory Service Manual is located in the stickies at the top of this section, I would suggest downloading it and checking the codes. No need for guesswork.


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## Lynx88 (Feb 7, 2005)

Ok, put it this way. I know what the codes mean... I have the service manual, but I don't exactly understand what I am reading. I have a good guess on how to fix codes 12 (air flow meter), 23 (throttle valve switch), and 41 (fuel temperature sensor). The cars old so more than likely those three things are not working or have bad connections. As for codes 11 and 21... on 11 mostly like is something called a crank angle sensor (never heard of it before), but it also list the starting system as a possible problem. 21 says something like "the ignition signal in the coil is not entered more than 10 times" and it lists about 7 possibilities. My best guess would be the distributor cap since it is all scratched up inside as if it had come loose while the engine was running. Just want a second opinion. Thanks


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## Zen31ZR (Mar 24, 2004)

Lynx88 said:


> Ok, put it this way. I know what the codes mean... I have the service manual, but I don't exactly understand what I am reading. I have a good guess on how to fix codes 12 (air flow meter), 23 (throttle valve switch), and 41 (fuel temperature sensor). The cars old so more than likely those three things are not working or have bad connections. As for codes 11 and 21... on 11 mostly like is something called a crank angle sensor (never heard of it before), but it also list the starting system as a possible problem. 21 says something like "the ignition signal in the coil is not entered more than 10 times" and it lists about 7 possibilities. My best guess would be the distributor cap since it is all scratched up inside as if it had come loose while the engine was running. Just want a second opinion. Thanks


 The crank angle sensor is basically the distributor. However, teh cap being bad has nothing to do that, the sensor itself is underneath. Check all the wires going to it.


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## Lynx88 (Feb 7, 2005)

So Zen, would you recommend replacing the air flow meter, the throttle valve switch, the fuel temperature sensor, and the crank angle sensor? Also do you thing the crank angle sensor will fix problem 21 as well?


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## Zen31ZR (Mar 24, 2004)

Lynx88 said:


> So Zen, would you recommend replacing the air flow meter, the throttle valve switch, the fuel temperature sensor, and the crank angle sensor? Also do you thing the crank angle sensor will fix problem 21 as well?


Considering all those problems are on the same side of the car, I'd look at the wiring and connections before I do anything else. The fuel temp sensor might possibly be bad, the throttle switch might possibly be bad. Check the wiring to the distributor and the MAF, you shouldn't replace those except as a last resort. If you have the FSM, it states how to test all those pieces, that's what I would do first.


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## Lynx88 (Feb 7, 2005)

I tested the fuel temp sensor and I know it is bad (too high of resistance). The throttle valve switch is busted, it broke to pieces when I took off the intake to do some work on the fuel lines. The MAF appears to have had work done to it already, it looks like someone opened it up (the rubber sealant I'll bet isn't factory). I did a visual check on the crank angle sensor and there is not any physical damage. The book I was using didn't really explain how to test the crank angle sensor, basically it said if it don't look broken, it ain't. As for the connections... my wiring harness is screwed. Most of the plugs are broken and some are corroded.


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