10

Hi!

 

I ran ECU diagnostic on my 300ZX TT and got code 21. Does this mean that the

Power Transistor Unit is destroyed? How could I be 100% sure about this? May

I use a voltmeter...what values should there be..?

Some tip where I should buy the PTU?

 

Thanks10 11

Here is the diagnostic procedure.

 

Does the engine run ?

 

What type of PTU does your car have ?

 

Does anyone know if there are still problems with the newer type ?

EgilTT

 

Code 21 means at some time whilst attempting to start the ecu did not receive an ignition return signal. The usual culprit for this is the cas unit as it does have a return signal to the ecu in order to trigger the injectors and the trigger input to the ptu.

 

 

Having said that when trying to start an engine that has failed to start, often several "tests" are performed to trace the problem from removing and cleaning connectors to actually undoing the cas unit and turning to see if the injectors and pump operate, these tests can actually result in spurious codes often false.

 

 

(Code 21 will definately occur if the cas unit fails or a poor

connection is present)

 

The ptu is triggerered on the low input side from the ecu based on input signals to the ecu from the cas unit and from there on the ptu is connected to the igntion coils so it would seem unlikely that the ecu can display any fault codes relating to no output at the ptu as there is no return signal from the ptu to the ecu.

 

Again having said that, the ecu will often sense other issue`s as previously mentioned that can give you clues rather than facts to the source of the problem, but when doing simple ecu code tests via the led or engine management light the information can be old ( up to 60 starts ago) so it is best to clear the fault memory (battery disconnect) and restart the procedure so as to remove any possibility of misinformation on the fault codes.

 

Once a clear base level is restored try the restart sequence again and pay attention to what order the tests are done in and although a pain take several oportunities to do an ecu test to see when a fault code (if it does) appears, this may help you to trace the source of the non start, alternatively a conZult test will speed it up greatly, maybe someone close to you can help out? Is ConZult available in Norway?

 

Jeff TT

Originally posted by VIPER

Here is the diagnostic procedure.

 

Does the engine run ? Yes!

 

What type of PTU does your car have ? It's a silver Al

 

Does anyone know if there are still problems with the newer type ?