One of the greatest or worst technological advancements in today’s automobiles is the Drive by Wire system or DBW for short. This electronic system replaces the traditional cable driven style throttle bodies of old, and replaces it with the complexity of motors, controllers and relays.
Drive by Wire for lack of a better term, is not conducive for enthusiasts looking to modify their vehicles. But that’s not stopping anyone with a Nissan 350Z or Infiniti G35 from strapping on a piggyback throttle controller such as the Sprint Booster or Buddy Club Throttle Booster.
Today we’ll be looking at how to test a VQ35 Accelerator Pedal, whether you own a G35 or 350Z or you are swapping a VQ35DE into another vehicle. If you own a vehicle with the VQ35 DBW system in it already, locate your pedal assembly. This is located under your dash and you will need to pull back the drivers seat as far as possible so that you can reach the pedal and connector.
The accelerator pedal position sensor (APP) is installed on the upper end of the accelerator pedal assembly. The sensor detects the accelerator position and sends a signal to the ECU. The Nissan Accelerator pedal position sensor has two sensors. These sensors are a kind of potentiometers which transform the accelerator pedal position into output voltage, and emit the voltage signal to the ECU.
In addition, these sensors detect the opening and closing speed of the accelerator pedal and transit that data real time to your Nissan ECU. The ECM computes the current opening angle of the accelerator pedal from these circuit inputs and controls the throttle control motor based on these signals.
Look under the dash, you are looking for the accelerator pedal and sensor, which is this gray six pin plug. Disconnect this plug to begin testing for power and ground at the harness.
Testing the VQ35 Accelerator Pedal for Power
We’ll be kicking off the How To Test a VQ35 Accelerator Pedal Guide with testing the VQ35 accelerator pedal for power. Using a multimeter, gently touch the front of the terminal harness to check for switched power. PIN 4 and PIN 6 are the two 5 volt power signals that should be sending 5 volts of power with the ignition set to the “ON” position.
Next you’ll be testing the ground circuits on your VQ35 accelerator pedal assembly, make sure to gently probe the front of the harness. Never insert your multimeter probes or leads down the front of a harness, as damage can occur to the metal clips or housing.
TESTING THE VQ35 ACCELERATOR PEDAL SIGNAL
Next part of our How To Test a VQ35 Accelerator Pedal Guide, you will be testing the circuits that send signals to your VQ35 ECU. Disconnect the VQ35DE ECU as well as the accelerator pedal, you will be testing for continuity between the accelerator pedal pin 5 or FPS MAIN and the ECU pin 106.
If the wire tests good and there’s no break or short in this wire, it’s time to measure the operation of your VQ35 accelerator pedal. Reconnect both the ECU and the throttle pedal, and you will be measuring the ECM with the help of a friend who can depress the accelerator.
The first wire we’ll be testing is PIN 106 on the VQ35DE ECU, this is the accelerator pedal position sensor 1. With the ECU and throttle pedal plugged in, you will be checking the voltage at PIN 106 on the ECU to see if your pedal is picking up the signal correctly.
Have your friend depress the gas pedal all the way down, and with the accelerator pedal depressed fully, you should have between 3.9 and 4.87 volts at wide open throttle (WOT). Now have your friend let off the gas pedal, and with the accelerator pedal fully released, you should have between 0.5 and 1.0 volts of signal.
If this step checks out, move onto the accelerator pedal position 2 circuit, which is PIN 98 on the VQ35DE ECU. Repeat the steps taken in the previous step, by having a friend depress the gas pedal all the way and let off while measuring both positions.
With the gas pedal pressed down all the way at WOT, the accelerator pedal position circuit 2 should read between 1.95 and 2.50 volts. With the gas pedal released fully, the APP2 circuit or PIN 98, the voltage should read between 0.15 and 0.60 volts.
Related OBDII DTC Trouble codes are P2127, P2128 which refer to the Nissan Accelerator Pedal Position (APP) sensor. If you find your accelerator pedal assembly is bad, replace it right away. It’s secured by two bolts to your chassis, the part number for automatic transmissions is 18002-AM81E for manual transmissions it’s 18002-AM81D.
This does it for our How To Test a VQ35 Accelerator Pedal article, if you have any questions about drive by wire or DBW, please leave us a comment or question below!