Best card diagnostic solutions
  • Fast Dispatch And
  • Highest Quality
    Standard & Safety
  • 100% Satisfaction
  • Best Value for
    your money
  • Great Customer

NISSAN CEDRIC Y34 VQ30DD NEO Di – diagnostic problems

NISSAN CEDRIC Y34 VQ30DD NEO Di - diagnostic problems 1

Without keyword

NISSAN CEDRIC Y34 VQ30 DD NEODi – diagnostic problems

In a previous article one of the standard malfunctions of engines with direct fuel injection was described, the solution of which took half an year from the owner. On the example of this car (as well as all similar others “coming” to the service), we continue to consider the reasons why such cars turn into trash.

As far as one can understand the owner of such a car, brought into a similar state, he was not particularly worried about errors like P1145, if it were not for one “little annoying nuisance” – the car will not start for three months. What nonsense – you say, and you will be wrong. Because the first month is nonsense, the second headache, and the third – complete depression: “what to do ?!” There are options to sell “as is” (but no one is buying a pig in a poke, if not for nothing), and the second is to perpetuate the creation of the Japanese automobile industry in his yard by making a pedestal. There is also a problem with the pedestal – in which direction should it be turned? In history, all the tanks are deployed in Berlin, but the car from Japan – turns east, or what? Somehow contrary to history and beliefs …

How do such creations get into a car service? Very simple – first, the garage twist of nuts, then club forums, then calls (annoying and distracting). After the 10th call, the owner realizes that according to the photograph the car cannot be repaired, that he himself will NEVER start it, and that his car is of no interest to anyone except himself. A month later, common sense defeats greed (for money) and a car is brought to a car service with the words: “do not make me incur debts”. And is it after three months of futile attempts to revive her anywhere? After such parting words, I really want to send the owner with his car to a nearby service for a couple more years. It keeps professional interest to understand (what happened in the end?), And the fact that the car was brought by a tow truck from another region.

The motor wiring is rewound all and rewound incorrectly. In addition, wrapping such insulating tape under the hood is complete nonsense, this is until the first summer and the engine is heated, then it dries and crackes. Essentially useless work, the result of which is even worse wiring condition than 12 years ago from the factory, photo 1

Why does this machine and their ilk have such operational problems? Everything is simply explained at the beginning of the previous article, plus the factor – the more complex the car, the more damage the car owner does to him.

There is another unit in this car besides the ECU in the cabin. This is the DUI injector amplifier block. The abbreviation DUI is: DRIVER UNIT INJECTOR. If in a simple way, then this is a high-voltage amplifier. It was used on the first generation NEO Di motors like QG18DD, VQ25DD and VQ30DD, but on QR20-25DD and second generation VQ25DD motors it is not. Two cars with a VQ engine of the NEO Di series had a similar nozzle control scheme – CEDRIC / GLORIA in the Y34 body and CEFIRO in the A33 body. At CEDRIC / GLORYA it is installed behind the left headlight, at CEFIRO – behind the right, opposite the generator, photo 2:

Amplifiers are absolutely similar on the VQ series and do not differ on motors of different displacement. Access to DUI CEFIRO pins is more convenient than CEDRIC. Next to the amplifier there is always a warning yellow sticker on which the symbols and hieroglyphics indicate the presence of high voltage and a ban on climbing anyone without observing the instructions. In Russia, no one has a decree to the owners, and not everyone can read it – so it turns out like this, photo 3:

DUI itself is very reliable and rarely crashes without external help. Although there were unsuccessful attempts to repair it. History is silent about what was originally, but “especially gifted specialists” obviously turned serviceable DUI into junk, judging by photo 4:

NISSAN CEDRIC Y34 VQ30DD NEO Di - diagnostic problems 2

DUI itself is not collapsible, but no one can forbid the owner to cut it in the garage, then give it for repair, after “repair and checking” with very competent electricians, start the car for another half-year. One of these DUI was saved. It turns out that the repair of most engine control units and others does not consist in actually repairing them (maybe they didn’t even need to be repaired). I am convinced once again: the repair of many “electricians – computer scientists” is that there would be know-how. Sometimes you hear such phrases from experienced drivers: – And what is there to change the microchip, something that is complicated … Well, yes, changing the chip is like grinding a cigar. Here, too, they changed the “microcircuit”, and so, God forbid, no one could repeat this miracle of repair, they erased the name. This is the know-how. Solder a couple of transistors, wipe their markings, shove the moment under the foam rubber and say: – That’s it, the block is ready. If it does not start, let the locksmiths from the car service look for a reason in themselves … photo 5

These are “proven” any blocks a dime a dozen in each case. There are certainly ways to check the block on the table, but not all parameters. The best way is the car itself. Most modern units with 120 conclusions, in my opinion, are not subject to a full check on the table, unless of course a trivial case, for example, there is no control on a gasoline pump or an error on the solenoid ….

There is no separate LAN-CAN bus for DUI control, therefore its diagnostics is carried out by an oscilloscope. Separate power supply cascades and the shaper circuit requires two fuses in the mounting block under the hood. The currents are not small – there is a separate relay switching the DUI power supply circuit, similar to the ECU used by NISSAN – brown with two pairs of short-circuit contacts. It is at the bottom left near the power cable from the battery to the mounting block, photo 6:

It can be seen that the car is not a tenant – the fuses are horrible, unoriginal (this has been written about many times) and those on which nothing can even be determined by a control lamp. The signatures of the mounting block are always saved, as they are on the inside of the cover, photo 7:

Even without knowing the Japanese language, by the coincidence of the characters and the alphabet, you can determine what is included in the DUI power group (relay – lower right). And then it’s a matter of technology: there is no one power supply on the DUI connector and the reason is in the mounting block – it’s not necessary to insert a special probe in the flat taps of the tester instead of a fuse. But only then the fuse back in such a connector has no contact with the lamella. And what’s the point of poking him with control from above? We bend one contact in the mounting block, insert the fuse back and the car starts after three months of “experiments”.

A very long time ago, Dmitry Yuryevich (nickname mek on the forum) took an oscillogram of the operation of the GDI MMC nozzle:

NISSAN’s analogy is complete. Only the voltage is higher, since the pressure is below 9 MPa. It is possible to fully capture the waveform, but it can only be useful theoretically in rare cases when there are doubts about the operation of the output stages. It should be remembered that the voltage is under 160 volts and the oscilloscope must be galvanically isolated, take measurements at the terminals of the nozzle from the DUI side without using the car body (mass).

In practice, it is enough to check the input signals. The duration of the input signals on the DUI is equal to the output, so if you have 4 ms on the waveform, then this is the case on the nozzle, and the reason is the low pressure of the injection pump. To control the operation of the DUI, a feedback signal is used similarly to TOYOTA’s IGT-IGF. In VQ series motors, two feedback signals from different banks (the even and odd side of the nozzles), photo 8:

Channel 6,7,8 – input pulses INJ from different channels, the missing pulse INJF indicates a breakdown of one nozzle (the owners tried – they wrapped twists), photo 9:

NISSAN CEDRIC Y34 VQ30DD NEO Di - diagnostic problems 3

And now the “dry residue” of the miserable car: the lamella in the mounting block is damaged by indefatigable handles with a tester. And it was worth 3 months to mock a car – it’s up to the owner himself..


  • Error P1145 and NISSAN CEDRIC

    Without keyword NISSAN CEDRIC / GLORIA Y34 VQ30DD NEODi and error P1145 Is it possible to repair a car if you really want to? It turns out you can, and…

  • CVT Transmission NISSAN CVT RE0F06A – Diagnostic Features

    Without keyword CVT NISSAN RE0F06A – Diagnostic Features Returning to the topic of repair of variator transmissions in previous articles, it became…

  • NISSAN CEDRIC Y34 VQ30DD NEO Di - diagnostic problems 4

    Nissan Almera B10

    Without keyword This car was produced from 2006 to 2012 and we can say that it was the last in the Almera lineup after the N16, which was made decently,…

  • NISSAN CEDRIC Y34 VQ30DD NEO Di - diagnostic problems 5

    CVT resource on the example of Nissan

    Without keyword Very heated discussions are held in all club forums about the advantages and disadvantages of CVT transmissions. Mostly they are scolded,…

About admin

Leave a Reply

Your email address will not be published. Required fields are marked *

© Copyright 2018 Carscanners. All rights reserved.

Enjoy this blog? Please spread the word :)