This is an awesome video explanation on Automotive Relays. Many Nissan Maxima members like to install high-performance cooling fans. If not properly installed using a relay, you can risk burning the wiring out. This has happened to us various times. The video below will help you understand how to do it correctly.
Screenshot Reference Photos
Member Credit: Matt Riney
For all you hardcore Nissan/Infiniti enthusiasts, there is finally an open-source solution that allows you to modify and flash ECUs! With a $10 VAG-KKL cable, you can basically flash your own ECU and tune it your to personal comfortable without breaking your wallet. The average tune costs roughly $600+ these days. Since you’re modifying the ROM yourself, there’s no vendor lock-in and you are free to do what you need and want. Great for those who have knowledge of tuning and want to tune their own vehicles!
Applicable Vehicles:
- 2000-2001 5thgen Nissan Maxima
- 2003-2003 5.5gen Nissan Maxima
- 2004-2008 6thgen Maxima
- 2009 7thgen Maxima
- 2002-2004 Nissan Altima
- 2005-2006 Nissan Altima SE-R
- 2003 Infiniti G35
- And various others……
Links to Tool/Software that you will need (Click links to Download):
- You will need to buy an OBD2 KKL VAG-COM 409.1 USB Cable. It costs $10 or less.
- Rom Raider (RomRaider 0.5.9 Release Candidate 3 – Released 09/28/2016)
- Java (Requires the latest 32bit (x86) version of Java SE JRE)
- Nisprog
- Npkern (Latest Version npk_7055_35.bin)
- Definitions
- Nissan Roms
Below are helpful videos on installing and running Rom Raider, along with dumping a Nissan SH7055 ECU with the Nisprog/Npkern software.
- Kernel 7055_35 is used by the early ecus 2002 & 2003 Maxima (and 2004 in most cases).
- Kernel 7058 is used for 05+ Maxima
- It’s all based on the ROM size. If the ROM size is 512K then you should use the 7055_35 kernel. If the ROM size is 1024K then you use the 7058 kernel.
Cars Tuned on ROMRaider / Nisprog
5.5 Gen Maxima Tuned by AdminTuning VQ35 Bolt Ons
Shaquille Jenkins 5.5 Gen Maxima Gen2 VQ35DE
Trevon Walters 4thgen Maxima Hits 11.77 (All Motor) Gen2 VQ35DE
Which ECUs Will This Work On?
Most gasoline Nissan / Infiniti ECUs from ~ 2002 onwards share very similar ECU hardware, based on SuperH microcontrollers manufactured by Renesas (previously Hitachi). This project supports ECUs that use the OBD-II “K line” signal for diagnostics communications.
How Does the Reflash Process Work?
The process is carried out entirely over the OBD-II “K Line” serial communications link through an undocumented set of manufacturer-defined extensions to the standard ISO14230 protocol. Recently, the necessary commands have been reverse-engineered revealing the required steps:
- Establish connection to the ECU.
- Send the first stage data payload: this is the “kernel”, a simple program that will receive commands and data for the reflash.
- Make the ECU run the kernel. From this point on, the kernel runs from RAM and effectively takes control of the whole ECU.
- Send the reflash commands and new firmware data to the kernel.
- Reset the ECU: the new firmware will now be executed, and the kernel will be completely removed.
Kernel Features
The basic kernel is an implementation of an ISO14230-compliant protocol with extensions. It implements the following requests:
- Fast ROM dump (tested up to 5.4 kB/s; typical speed is ~100 B/s without a kernel)
- Read ROM/RAM/external EEPROM
- Write to RAM
- Erase flash ROM block
- Write flash ROM block
Requirements
The basic reflashing kernel will support gasoline ECUs with:
- SH7055 or SH7058, 0.18um microcontrollers (the most common types)
- K line wired to the OBD-II connector pin 7
- Unfortunately CAN-only ECUs are not currently supported.
Host computer:
- OS: Linux and Windows are known to work; Nisprog is based on freediag source code which is cross-platform and should run on most Linux/UNIX flavors.
- Connectivity: a simple USB-OBD adapter is required. These are the “Generic dumb serial adaptors” described in the freediag docs.
OBD2 KKL VAG-COM 409.1 USB Cable
Limitations
There are several important points to be aware of when using Nisprog:
- The ECU is a safety-critical system in a car. Reflashing an ECU can void warranties, reduce the vehicle’s reliability, and cause a whole variety of undesirable consequences. Use of this project and any associated tools (freediag, Nisprog, etc) is of course entirely at the user’s risk. Standard disclaimers apply.
- Reflashing an ECU may be illegal in some areas. Responsibility in this matter lies again with the user.
- Diesel ECUs are not supported, they are entirely different.
- Tuning and modifying ROMs are complex skills that can only be acquired through significant investments of time and effort!
When looking for parts, you usually refer to them as driver side or passenger side. However, there are often times where all you see is either an “LH” or “RH“. While it may seem self-explanatory, there are some people who get it confused and end up ordering the wrong parts. So here’s what they mean (for USA based vehicles):
LH = Left Hand (Driver Side)
RH = Right Hand (Passenger Side)
Example: The fender below says RH. This means it’s for the “Right Hand Passenger Side”.
Credit: Rene aka https://www.youtube.com/user/carsnwomen91
Please subscribe to show them support!
Part 1 – Introduction
Part 2 – Inspecting and Opening the Motor
Part 3 – Timing Chain Assembly
Part 4 – Cam Trigger Wheels
Part 5 – Trans Swap, First Start-Up
This post if for folks looking to install SPAL Fans into their Maxima. These are quality high-speed fans that are great for both N/A and Boosted Setups.
PDF Instructions:
Overview:
We designed the SPAL fan wiring harness to enable the simplest installation of our performance fans. It is compatible with all types of vehicles and can be installed on positive or negative ground vehicles with no modifications
- 185 Degree Thermostat Controlled Relay (185FH)
- 195 Degree Thermostat Controlled Relay (195FH)
Installing the fan:
When installing electric cooling fans, it is important to cover as much surface area as possible. Mount the fan as high up on the core as possible. Attach the fan to the small area around the core of the radiator where there is a metal lip that is approximately 1/4″ to 3/8″. This will allow mounting of the fan(s) without compromising the core of the radiator.
Wiring:
Mount the relay in a secure place in the engine compartment away from heat sources. Once this is completed, connect the wires per the diagram and notes below.
- Red: Connect to the red wire of fan pigtail with pre-terminated yellow crimp.
- Gray: Connect to thermostat socket (sending unit) with blue ring crimp connector.
- Yellow: Connect to positive battery terminal using the fuse holder and yellow crimp connectors per diagram (see back).
- Orange: Connect to ignition switch +12 vdc when engine is in run position. (Hook to constant +12 vdc for the fan to run continuously when the engine is hot even when the ignition switch is off).
- Black: Connect ring terminal to chassis ground.
- Fuse Holder: Connect fuse holder inline per diagram within 12″ of the battery using ring terminal or equivalent.* Note: On medium profile fans use a 20 amp fuse, on low profile fans use a 15 amp fuse
Installing the Thermostat Switch:
The sensor has 3/8″ pipe thread. The thermostat supplied with the kit is an OE type that is designed to mount in the cylinder head of the engine. However, any mounting in water jacket is suitable. The 195FH sending unit comes on at 195 degrees and off at 175 degrees. The 185FH module turns on at 185 degrees and off at 165 degrees. The modules will work on the majority of applications. If a different size adapter is needed, the correct size thread adapter can be found at most automotive parts or hardware stores (1/2″ adapter included in the kit) . Do not use Teflon tape on the sensor it can cause poor electrical contact and incorrect temperature readings.
Wiring Diagrams
If you don’t use a good relay like the one above, this will happen (Photo Courtesy of Javon Bennet)
Original Music Credit: TrixXx (Brian B.)
I was finally able to get a hold of Brian who made this song back in 2009 for the Maxus09 event. I couldn’t find it for years. But here it is. This deserved its own official post.
Thanks Again Brian.
If you are reading this article, you are very likely trying to resolve P0420/P0430 without having to spend a lot of money on the issue. Most of the time, the codes are due to a bad clogged catalytic converter or bad O2 sensors. Before replacing the O2 sensor, be sure to do the spacer fix modification first because O2 sensors are not cheap.
There aren’t usually any drivability issues associated with these codes. For most people, the first sign that anything is wrong at all is the check engine light. Below are the typical check engine lights you would normally get:
- P0420 NISSAN – Catalyst System Efficiency Below Threshold Bank 1
- P0430 NISSAN – Catalyst System Efficiency Below Threshold Bank 2
The Fix
You can eliminate the codes by using a spark plug non-fouler which tricks your engine computer to think that everything is working fine. This simple trick will pull the O2 sensor away from the exhaust flow and the computer will think the Catalytic converter is working properly. This will work if you remove the catalytic converter or have a bad cat. It’s very simple and cheap to do. Below is a video on how to perform the fix:
You can also buy them pre-made on eBay if you do not want to drill.
Make Your Own Spacers/Foulers
You can buy these non-fouler spacers at your local parts store. You can get them from Advanced Auto or Autozone for about $7-8 bucks.
You now need to drill out 1 of the non-foulers using a 1/2″ drill bit. When finished this is what it will look like.
O2 Sensor inserted in the modified non-fouler
Second, unmodified non-fouler now installed on modified non-fouler, then threaded into the pipe
Reference Photos
Below are photos of the spacers installed and 100% working on Nissan Maximas by generation. After installing the spacers, the CEL codes went away.
5thgen Nissan Maxima
6thgen Nissan Maxima
7thgen Nissan Maxima
Member Credit: xlack
This is from a G37 but the procedure pretty much identical to Nissan Maximas.
OEM Oil Pan completely stripped of silicon residue:
JWT Oil Pan Spacer:
New silicon applied:
Brush used to remove silicon remains: 
This bolt has to be bended in order for the oil pan spacer to fit. (guy from 370z forum had it cut off, but is not necessary):
Bolt is knocked back into position: 
