Z32 Code 11 and 21

Discussion in 'Technical' started by Pamandal32, Aug 15, 2022.

  1. Pamandal32

    Pamandal32 New Member

    Hi - I've just done the code reading using the paper clip method on my 1989 TT 300ZX. Code 11 and 21 came up 11: Crankshaft position sensor circuit and 21: Ignition signal circuit. Is this an auto electrician fix or something I can bolt on myself? Appreciate and advice. Al

    ADAMZX 2000spec Conversion

    I would suggest you check your electrical connectors on both your crank angle sensor and ptu and look for green corrison on the pins.

    If theres corrison you'll need to strub the connectors clean and remove as much of the corrison as possible using battery terminal cleaner.

    Also the codes can only to be cleared using the conzult program which you can download from the internet for free.
  3. Pamandal32

    Pamandal32 New Member

    Hey Adam - thanks for that. I'll check all the connectors tomorrow and do a clean up. The car has been sitting for ages so there may be some deposits there.

    Here's hoping

  4. rob260

    rob260 Administrator Staff Member

    Before you do anything... and especially before you replace anything...

    1. Follow the banner link at the top of this page to the tech section
    2. Download the Factory Service Manual
    3. Navigate to slide EF & EC 42 and locate the diagnostic procedures that match to your fault codes
  5. Pamandal32

    Pamandal32 New Member

    Hey Rob - now THAT'S a document - some good bedtime reading. But I navigated to the sections you mentioned (and thanks for that guidance) and found as Adam suggested, to check the connections on the sensor and PTU. There's 1200 pages of good info. I think a morning in the sun cleaning the connections will be a very good place to start. Thanks for getting back to me. Al

    ADAMZX 2000spec Conversion

    I would say that the fsm is the bible we all as 300zx owners need to study in detail.

    But in a time of urgency, i have provided you with my 16 years of z32 experience in quickly troubleshooting a suggestion that ive dealt with myself and could possible be the cause of your problems and is a good simple first step to diagnosing your problems in the short term.

    But in the long term you may need more hands on mechanic help and or trial and error to repair the issues your experiencing.
  7. rob260

    rob260 Administrator Staff Member

    Ok so here's the thing about trouble shooting and diagnostic procedures....

    Firstly anybody reading should undertake (or not) whatever level of maintenance and diagnostics they're comfortable with.


    If we take the code 21 for example. This can be caused by failed power supply, failed pulse signal, failed ground circuit, or a failed ECU. If your problem is caused by poor contacts on the PTU connector this will present as an absent pulse signal, at which point you can inspect the PTU and harness continuity as per the FSM. Poor contacts might result in poor or absent harness continuity between the ECU and the PTU, or the PTU and the ignition coil, or both. Unless we have different editions of the FSM nowhere does it mention to check the connections, although as I mentioned poor connections might be indicated via one of the tests (that is conducted after checking for power and ground) that is mentioned in the diagnostic procedure.

    You've made it this far, it will ultimately be cheaper, more time efficient, and more rewarding to diagnose the problem than to rely on anecdotes or trial and error.

    Or if you don't have the tools and the know-how (which is a position we've all been in at one time or another) you might benefit from hooking up with a local member or mechanic who does. Your profile says QLD, if you're in Brisbane member @rollin operates Briseuro and would be able to help you out.

    Happy hunting.
    Last edited: Aug 16, 2022
    ZOE NZX300 likes this.
  8. Pamandal32

    Pamandal32 New Member

    Hey Adam and Rob - well I began the process as you guys have described and quickly put away my tools. I could see I was going to either break or maim something, so I went to the next step - phone an auto electrician. There is a quite well known one here in Noosa and so I have booked the Z into him. Interestingly one of the young fellas there came up and chatted as he also has a Z. So I could be in good hands. I will tell them about the codes I found and see if that helps. I also have a heater not working and a funny thing happening with the ignition which I am thinking may be linked to the PTU. SO I will give them the car and perhaps a kidney as down payment, but it will be good to get sorted. Thanks a million to both of you for your tips and guidance.
    ADAMZX likes this.

    ADAMZX 2000spec Conversion

    I too do agree with you rob with everything you have said and it only took me like 10 years of z ownership to realise how important the fsm is to maintaining our cars and how to diagnose sensors and so forth.

    Hiwwever what i have suggested was not a complete diagnostic solution for the thread maker but an educated experience guess to the 21 error code which i experience first hand for several months with my car, occasionally not starting in the mornings and or stalling and not starting irregularly. I didnt have a clue what the problem was at first and assumed it was fuel related so i changed the fuel filter thinking it was blocked but that did not fix my problem.

    After several more instances of my none starting issues and being fed up with it, i finally decided to tackle the issue and when i looked the error code up like what you have suggested in the fsm, it directed me to a failed ptu unit but as i have a series 2 ptu installed, i was sceptical as they are not normally prone to failure. Anyways i decided to check the adaptor harness on the ptu and what did i find, green corrison on all of the series 1 connector pins which i was able to the conclude was my culprit and after thoroughly cleaning the connectors and removing as much of the green corrision as possible, guess what, my problems were solved and the error 21 code has not come back since.

    Now maybe i was lucky and i still did have to use the fsm to at least narrow my problem down so what i suggested may of may not help him but its a good start in my opinion and it wouldnt take the cost of mechanic charging $100 p/r to simply check the connectors yourself just incase the problem is a simple one to fix.

    I think the moral of the story is that if you plan to tackle mechanic and or electrical problems yourself, you need to do thorough research on the symtpons using the fsm as much as possible and if a solution exists, you should follow the fsm to the letter for a solution. And if you cant find the solution then you can ask the dumb questions and maybe get some free help from one of the many knowledgable experience 300zx owners on this wonderful forums.
  10. Pamandal32

    Pamandal32 New Member

    You have been a great help Adam - appreciate you taking the time to share your knowledge and experience. Both you and Rob have provided good guidance. Ultimately with my history of mechanical disasters I erred on the side of caution and will let the auto electrician do the work. Wish I had you guys ability and skill, but I love my Z too much to do it a mischief. Will let you know how I go. Thanks for taking the time to help. Al
    ADAMZX likes this.
  11. ADAMZX

    ADAMZX 2000spec Conversion

    And thats completely up to you mate and i hope that the issues you are experiencing will get fixed by the people your taking the car too. But please do post what they ultimately find at fault as im curious to see if im right or if im wrong on the matter.

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