350Z and G35 Pedal Calibration for LS Engine Swap Applications

How to recalibrate the APPS in a 350Z or G35 for LS Engine Applications

Stock 350Z Accelerator Pedal

A drive by wire pedal is simply a pair of variable resistance sensors that the ECM reads to determine the drivers pedal input. The ECM refers to these two inputs as APP1 and APP2, or Accelerator Pedal Position Sensor 1 and Accelerator Pedal Position Sensor 2, respectively. While the pedal only physically has one sensor on it, that one physical sensor has two independent sensors in it, the two sensors are built in one. It is important to note that these are NOT "Throttle" Position Sensors. The Throttle Position Sensors (TPS1 and TPS2) are built into the drive by wire throttle body, NOT the pedal!!

APP Sensor on Pedal Assembly

The two APP sensors output a variable voltage depending on what the position of the pedal is. One sensor is a 0-5V output, and the other is a 0-2.5V output. In a perfect world, zero pedal position would be 0V on both sensors and a "floored" pedal would be 5V and 2.5V on the two APP sensors. However, this is not how variable resistance potentiometers work. In reality, zero pedal application will be slightly above 0V, and full throttle will be slightly less than 5V / 2.5V.

Here is where things get tricky. The factory Nissan ECM and the factory GM ECM have a voltage range that they like to see. If they see a zero throttle applied APP voltage under a certain value or a full throttle APP voltage over a certain value, they will trigger a Check Engine Light for an error on the APP input. However, the Nissan ECM has a wider tolerance than the GM ECM. The GM ECM will trigger a P1277 or P1282 code if either voltage output from the pedal sensor falls below 0.32V. This will result in a dead pedal and a limp mode condition. This can occur when wiring the Nissan pedal to the GM ECM, since the Nissan ECM will tolerate a lower voltage input than the GM ECM will. To check the voltage that your APP sensor is currently outputting, you need to connect either a OBD2 scan tool that can read live data, or HP Tuners Vehicle Scanner. With Key ON and Engine OFF, look at live data, specifically APP1 and APP2 Voltage, not percentage!

APP1 and APP2 Voltage with Pedal at Rest, Good Values
APP1 and APP2 Voltage at WOT, Good Values

If either of these values are under 0.32V at rest, you will have an issue that will cause a CEL and limp mode. Fortunately, there is a very simple fix for this! The APP sensor on the Nissan pedal is held to the pedal assembly with two screws and it can be calibrated. With your OBD2 scan tool or HP Tuners connected to the vehicle with Key ON Engine OFF, loosen the two screws holding the APP sensor to the pedal and rotate the sensor until both values are over 0.32V. It's a good idea to target 0.38V on the lower of the two sensors. Once set, tighten the screws, reset any stored codes, and you'll be good to go!

 

Red Arrows Indicate Retaining Screws to be Loosened
Green Arrows Show Rotation of Sensor