The infamous VPC harness, showing the resistor-side up.
The F-Con harness can be seen toward the top of the photo.
VPC HardWire-'87/'88 ECU & Dipswitch Settings
There are two major reasons for hardwiring the installation of the HKS VPC:
I have the necessary harness, so the reason behind this painstaking documentation of the hardwire was
due to the latter. The hardwire diagrams depicted are as accurate as could be determined from
reverse engineering the VPC harness, & careful examination of all related OEM wiring. Understand that
I cannot be held liable if you use this information; whether it contains errata, or not.
VPC Harness Photos
The infamous VPC harness, showing the resistor-side up.
The F-Con harness can be seen toward the top
of the photo.
The infamous VPC harness; VPC headunit wiring side up.
The F-Con harness can be seen toward the top
of the photo.
Harness Wire Colors for the OEM 24-pin *R* Connector
Image depicts the OPEN side of the connector.
If confused, refer to the wire colors to verify.
| Pinout # | Color |
| 3 | Blue/Red Stripe |
| 4 | Red/Black Stripe |
| 5 | Light Green [or Blue]* |
| 13 | Black/Red Stripe |
| 15 | Light Blue/Red Stripe |
| 24 | Brown |
Harness Wire Colors for the OEM 18-pin *T* Connector
Image depicts the OPEN side of the connector.
If confused, refer to the wire colors to verify.
Pinout #
Color
3
Light Blue/Brown Spots
Diagram of VPC Harness Wiring to ECU Harness
ECU Connectors, viewed from the rear
These are the VPC's wire colors & their corresponding location on the ECU connectors,
labeled connectors 'R' & 'T' in the TSRM.
The wires coming from the VPC simply get spliced into the wires indicated by the pinouts.
Use whichever splicing method you prefer, but I recommend soldering.
Before you begin the wiring process, see the resistor diagram in the next section below. Splicing of the Black/Brown Spots VPC wire needs to be done before the resistors.
| VPC Wire Harness Color | TO | Pinout # | ECU Harness Wire Color |
| Red/Black Spots | 24-pin *R* Connector | 13 | Black/Red Stripe |
| Gray/Brown Spots | 24-pin *R* Connector | 15 | Light Blue/Red Stripe |
| Black/Brown Spots | 24-pin *R* Connector | 24 | Brown |
| White/Brown Spots | 18-pin *T* Connector | 3 | Light Blue/Brown Spots |
Diagram of Resistors in the VPC Harness
Note #1: The tolerance stripe on the resistors is gold; IE, go for the gold!
Note #2: The Black/Brown Spots VPC wire gets spliced in before the resistors.
Note #3:
Wires at Pinout #4 [Red/Black stripe], & pinout #5 [Light Green] are cut;
IE, they no longer provide signal to the ECU. Be sure to leave sufficient
excess on the connector side to enable wiring in of the resistors.
This diagram depicts the resistors that are placed in the wiring between the harness & the ECU
connector. Why does it look like a cluster fu<#?
The most commonly held belief is due to the exclusion of the High Altitude Compensation [HAC]
component of the engine management. The '89+ ECUs, have the HAC integral to the ECU, which means a
hardwire to that version of ECU is more straightforward. There is a resistor, but only 1, instead of 3.
If I ever get the diagrams for hardwiring the VPC to the newer ECU, I'll be sure to update this page.
NOTE the orientation of the stripes. I don't think there's polarity in resistors, but don't tempt fate- orient them as
they appear. At least 2 of them are the same kind of resistor. AND, they are a LIGHT tan base color, not dark as in the
pic; if that makes a difference. I studied the thing long & hard, since I'd like to dump the harness myself, so you
can rest assured...I looked at it LONG & HARD before I drew it up as shown here.
VPC Internal Dipswitch Settings
This pic shows the internal dipswitch settings for the VPC,
regardless of what year Supra you run.
Thanks go to Stanward Oshiro for the pic.
