"How do I know if my STVA has failed?"
The simple answer is that the bike will tell you. All of the fuel injected bikes have a self diagnostic system that will detect and identify the problem. Under normal conditions, the fault indicator on the dash will come on (just a red light), and the LCD will display "FI" in the coolant temperature area of the LCD. There's some disagreement among those in the GSX-R community about the meaning. Pe
"How do I access dealer mode and what can I do with it?"
Accessing dealer mode is very simple. First you need to locate the diagnostic plug. After you remove the driver seat, look back here.
It should have a black rubber cap on it.
After you remove the cap, you'll see a 6 port plug. Pay attention to the orientation shown here. It's the two pins marked with arrows.
This shows mine jumpered with a piece of 24 gauge wire I harvested from an old phone cord.
Along with the code, you see a dash to the left "-C28". When everything is working good, the code reads "-C00". The dash is actually used to easily calibrate the throttle position sensor (TPS). In the middle, it's just right. If it's below " _C00 " then the TPS is adjusted too low. If it's high " -C00 ", then the TPS is set too high. Be aware though, the TPS will read high with the bike in p
This is what it will look like with no FI codes. A note about the TPS adjustment. It needs to be done with the bike fully warmed up and running at idle. Also, a lot of people mistake the sensor mounted to the STVA as the TPS. It's the secondary TPS. The TPS is mounted below the STVA and has a grey plug. Adjusting the wrong sensor will just cause you more headaches. Slow down and make sure y
There are three basic parts to the SDTV system. The STVA assembly (sensor and actuator), the wiring harness, and the ECU. The ECU is impossible to test for the home mechanic. The STVA and the wiring is very easy to test. If both of those are good, the only thing left is the ECU, so we start at the STVA and work our way back. Before we start, it's important to know that the sensor is spring loaded
This shows the cam in the fully open (fast idle) position. The secondaries are fully open here.
To remove the STVA, you'll want to first remove the driver's seat and prop up the tank. The last thing we want to do is cause more damage to our bike, so we're going to tape over the frame to protect it. I'm using 2 layers of regular masking tape to do the job.
Be careful not to damage the plug. The tip of the screwdriver is pressing in on the locking clip. Try it with your finger first.
This is the main plug for the STVA. It's hinged. The tip of the screwdriver is pressing in on the release. Try it with your fingers first.
Larger connector removed from the ECM.
Once it's removed, you can look into the wiring harness. Again, with the plug on top, we're going to think of this as two rows of 17 ports. Port 1 is the top row, far left. On most bikes, it's marked like this one. The ports go across the rows 1-17. Port 18 is directly below port 1 and the bottom row is ports 18-34.
These ports are tiny, and the contact socket inside is thin. If you're forceful here, you can make them loose and make things worse, so be very delicate in the next steps. To duplicate the STVA tests, we'll test both circuits again. Obviously the STVA needs to be connected again. This shows the left circuit are ports 1 & 18. The best way to do this is with sewing pins clipped in the gator clips o
Here again with the right circuit, pins 2 & 19.
For the purposes of these instructions, we'll assume you found infinite resistance on the left circuit. There are two wires here, so we need to test both independently. Similar to the previous test, we need to test port to port. This time, we're going to test from the ECU connector port, to the STVA port. The image below shows the port mapping from the ECU connector to the STVA connector.
Here we have the black lead connected to the port for ECM pin 1 on the STVA connector.