2003 G35 Sedan

This is meant to supplement the installation instructions to the LMA-3 (“AuxBox”) for the said specific model vehicles. The desired sensors can be chosen from the list below and it’s appropriate setting for scaling of the sensor’s output voltage into meaningful performance unit readouts (e.g. percentage of throttle body opening instead of a 0.36 to 4.7V raw readout) be programmed into the LogWorks software. Some sample input configuration files are included here for some common forced induction and naturally aspirated applications.

I. Built-in Sensors.

Disconnect the negative battery terminal before unplugging the ECU connector. The ECU (ECM) can be found under the passenger-side glove compartment. After unplugging the connector, remove the black locking lever by snapping it out of its anchors in the middle of the connector. Remove the outer harness ‘collar’ that helps retain the wire bundle in place. Locate the appropriate wires for the desired sensors that you want to use according to the terminal number and the wire color, as described below. Here is the terminal layout of the ECU harness (rear “harness” side shown here):

The useful sensors and connections are listed in the table below, along with the appropriate scaling to be used to interpret the raw sensor voltage into meaningful data (where appropriate).

 

Terminal	Sensor Name	Wire Color	Voltage Range	Conversion factors, Comments
5	RPM Signal – Ignition Coil Cyl #1 (RPM)	Yellow/Red	N/A	N/A*
1	Injector Duty Cycle (Dwell) – Inj. #1 (DWELL)	Red/Black	N/A*	N/A*
66	Intake air temperature sensor (IAT)	Yellow/Green	Approx. 0 – 4.8V	234 ° F (112 ° C) = 0V -3 ° F (-19 ° C) = 5V
83	Throttle position sensor (TP)	White	0.36-4.75V	-13% = 0V 122% = 5.0V **
93	Engine coolant temperature Sensor (ECT)	Yellow/Black	0-4.8V	238 ° F (114 ° C) = 0V -5 ° F (-21 ° C) = 5V
62	Mass air flow sensor (MAF)	Light Green	1.1-5V	N/N …
73	Accelerator pedal position sensor (APP)	Brown	Approx. 0.41-3.2	-13% = 0V 122% = 5.0V **

* Not applicable. A built-in LMA-3 sensor used.
** TP and APP sensor values are approximate. Verify the raw voltage with the pedal depressed and released on your own car and use those voltage values for 100% and 0% TP/APP, respectively.
… Not needed. Voltage itself monitored for tuning purposes.

 

II. Automatic Transmission Sensors:

Some useful temperature information can be found by tapping the TCM (Transmission Control Module) harness (the front “terminal” side shown here).
 

 

Terminal	Sensor Name	Wire Color	Voltage Range	Conversion factors for LogWorks
8	ATF Temp Sensor 1	Black/Orange	0-2.x	32 ° F (0 ° C) = 2.2V 176 ° F (80 ° C) = 0.6V (normal operating temps 60-80 ° C)
17	ATF Temp Sensor 2	Green/Red	0-2.x	32 ° F (0 ° C) = 2.2V 176 ° F (80 ° C) = 0.45V (normal operating temps 60-80 ° C)

 

III. Additional Sensors.

Additional sensors can be purchased and installed to add to the stock sensor repertoire. These sensors must be of the 0-5V output. The following sensors appear appropriate for this purpose but have yet to be tested. Check for an updated version of this document in the coming weeks for specific information (test results and voltage scaling).

Sensor	Sensor Name	Voltage Range	Conversion factors for LogWorks
Fuel Pressure	Autometer fuel/oil pressure sending unit Part # ATM-2246	Aprox. 0-5V
Oil Pressure	Autometer fuel/oil pressure sending unit Part # ATM-2246	Aprox. 0-5V