The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support Rix Racing

1G The 1990 Engine Control Wiring Harness

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

*****IMPORTANT*****
Note that the wire color layout diagrams accompanying each picture are as seen FROM the CONTROL HARNESS SIDE of the connector with the release tab (for a male side connector) or locking notch (for a female side connector) on top. That is, you are looking at the wires going into the connector, OPPOSITE the side that is pictured. Like this: How to identify ECU pin numbers.
*******************

This is the ENGINE CONTROL harness. If you want information on the ENGINE COMPARTMENT harness, see: The 1990 Engine COMPARTMENT Wiring Harness.

As we all know, the 1990 model year had many quirks to it when compared to the later model 1Gs. Because this was a single (and the first) year of the Eclipse/Talon/Laser trio, information on these cars isn't nearly as abundant as 1991-1994 models.

I don't plan to dive into and explain the differences between these models as there are plenty of threads around naming the differences. In short, this article is a configuration diagram. It aims to familiarize members with the 1990 4G63 turbo engine control harness electrical connections, similar to what snowborder714 did in his 2g Engine Bay Electrical Connections article, but not nearly as thorough. To be clear, this article does not cover every electrical connection in the 1990 engine bay, only those on the engine control harness, including the handful of interior connections. For your convenience, the 1991 configuration diagrams are provided.

You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


As a couple extras, it will touch on some connector differences that must be attended to when swapping a 1990 turbo engine control harness into a later model 1G or vice versa (these are denoted by **). It lists original wire colors and original individual wire locations as viewed from the wire side of the connector as well as a visual of each connector on the harness.

Also, for comparison, here is a similar page for the later model 1Gs (those connectors labeled with * are either completely different, in a different location, or non-existent on the later model 1Gs): 1Gb DSM 4G63 Turbo Wiring Harness Diagram

First and foremost, the main harness itself. The alphanumeric identifiers relate to those in the 1991 configuration diagram found in the electronic copy of the factory service manual: Download the 1G Service Manuals. The harness displayed here is a 1990 turbo engine harness which, by consequence, means it is from a vehicle with a manual transmission.

Click to enlarge slightly or zoom by pressing Control and + (the plus sign):
You must be logged in to view this image or video.

To shrink, press Control and - (the minus or negative sign).

A-08: Dual Pressure Switch (black connector, 2-pin)
A-09: Wiper Motor (black connector, wide rectangular 4-pin)
A-10: Control Wiring Harness and Battery Cable Assembly Combination / Starter Wiring Harness and Reverse Light Switch (black connector, square 4-pin)
*A-11: Auto-Cruise Control Actuator (black connector, square 4-pin)
A-12: Brake Fluid Level Sensor (black connector, stacked 2-pin)
A-13: Control Wiring Harness and Solenoid Valve Harness Assembly Combination (black connector, rectangular 6-pin)
A-36: Air Flow Sensor (black connector, NT 6-pin, Turbo 8-pin)
A-51: Waste Gate Solenoid (black connector, stacked 2-pin)
A-52: Control Wiring Harness and Engine Compartment Wiring Harness Combination (black connector, wide rectangular 4-pin)
A-53: Control Wiring Harness and Engine Compartment Wiring harness Combination (black connector, large 1-pin)
A-55: Fuel Pump Check Connector (black connector, small 1-pin)
A-56: Noise Condenser (black connector, very small 1-pin)
A-57: Defogger Relay (black connector, 5-pin)
A-58: Injector Resistor Pack (black connector, rectangular 6-pin)
A-59: Engine Speed Adjustment Connector (black connector, small 1-pin)
A-60: Ignition Timing Adjustment Connector (black connector, 2-pin)

*B-00: Noise Filter (for Tachometer) (black connector, stacked 2-pin)
B-01: Injector No. 4 (black connector, 2-pin)
*B-02 & B-05: Throttle Position Sensor and Idle Switch (black connector, square 4-pin)
**B-04: Idle Speed Control Actuator (black connector, rectangular 6-pin)
B-06: Injector No. 3 (black connector, 2-pin)
B-07: Detonation (Knock) Sensor (grey / gray connector, 2-pin)
B-08: EGR Temperature Sensor (black connector, 2-pin)
B-09: Injector No. 2 (black connector, 2-pin)
B-10: Injector No. 1 (black connector, 2-pin)
*B-14: Ignition Coil (Coil Pack) (black connector, square 4-pin)
*B-15: Power Transistor Unit (black connector, straight 6-pin)
B-16: A/C Magnetic Clutch (black connector, round 1-pin)
B-26: Oxygen (O2, 02) Sensor (black connector, round 4-pin)
B-29: Engine Coolant Temperature Gauge Unit (black connector, small 1-pin)
B-30: Engine Coolant Temperature Sensor (for ECU) (black connector, stacked 2-pin)
B-31: Engine Coolant Temperature Switch (for A/C) (black connector, 2-pin)
*B-32: Crank Angle and Top Dead Center Sensor (Cam Angle Sensor, CAS) (black connector, square 4-pin)

C-56: Oxygen (O2, 02) Sensor Check Connector (milk white connector, small 1-pin)
C-57: Control Wiring Harness and Body Wiring Harness Combination (milk white connector, 1-pin, passenger side kick panel)
**C-58: Control Wiring Harness and Body Wiring Harness Combination (white connector, 16-pin, passenger side kick panel)
C-59: Control Wiring Harness and Body Wiring Harness Combination (milk white connector, 6-pin, passenger side kick panel)
C-63: MPI Control Relay (milk white connector, 10-pin)
C-64: MPI Control Unit (ECU, small connector) (yellow connector, 10-pin)
C-65: MPI Control Unit (ECU, medium connector) (yellow connector, 18-pin)
**C-66: MPI Control Unit (ECU, large connector) (yellow connector, 24-pin)
**C-67: Control Wiring Harness and Body Wiring Harness Combination (under center console) (white connector, 8-pin)

The wire color layout diagrams accompanying each picture are as seen FROM the HARNESS SIDE of the connector with the release tab (for a male side connector) or locking notch (for a female side connector) on top. They should be color coded correctly, but if there is a disagreement with the letters and the color of the letters, go by the letters. When two colors are listed together, the first is the main color and the second is the color of the stripe or tracer. The letters represent the following colors:

B - Black
W - White
R - Red
G - Green
L - Blue
Y - Yellow
O - Orange
Lg – Light Green

PM me if you find any errors and I will make corrections as necessary.

Finally, the following supporting vendors supply the individual connectors linked or partial kits for different model year DSMs:
JNZ Tuning
Extreme PSI
Magnus Motorsports

At the end of the day, they are all coming from Sheridan Engineering.

You must be logged in to view this image or video.
To relate wire sizes from your FSM (metric) to AWG sizes: The Engineering Toolbox - Wire Gauge Converter.
 

Attachments

  • 90Control_Harness_Configuration_Diagram001.jpg
    90Control_Harness_Configuration_Diagram001.jpg
    56.7 KB · Views: 2,734
Last edited:
B-10: Injector No. 1

Connector available at: JFC 2P.
 

Attachments

  • B10_Injector11.jpg
    B10_Injector11.jpg
    28 KB · Views: 457
Last edited:

Attachments

  • B14_IgnitionCoil1.jpg
    B14_IgnitionCoil1.jpg
    33 KB · Views: 663
Last edited:
B-15: Power Transistor Unit

A six pin connector compared to eight pins for the 1991+, the 1991 has extra wiring here because this is where the tach signal is generated. See this for more: 1991-1994 ecu swap into a 1990 DSM ignition wiring

The 1990 Power Transistor Unit (PTU) connector is available at: JFC 6P.

For you 1991+ users or those interested in converting their 1990 to use the 1991 ignition system and missing the connector, that connector is available at: CON-2GMAF-8F.
 

Attachments

  • B15_PowerTransistorUnit2.jpg
    B15_PowerTransistorUnit2.jpg
    33.4 KB · Views: 592
Last edited:
B-16: A/C Magnetic Clutch
 

Attachments

  • B16_MagneticClutchAC1.jpg
    B16_MagneticClutchAC1.jpg
    29.3 KB · Views: 569
Last edited:
B-26: Oxygen Sensor

If there is a need to wire up an aftermarket O2 sensor and you are unsure how to do so, please read: Oxygen Sensor Wiring

If you found the available 1G replacement connector through one of our vendors, proceed to purchase with caution after reading this product review: Oxygen ( O2 ) Sensor Connector from OHM-Racing.

If salvaging your old connector, new pins can be sourced without buying a whole new connector. Here’s a thread with the part number information: 1G O2 Sensor Connector Pins

@brads has informed me that the OEM 1G O2 sensor is discontinued. JNZTuning has recommended using the 2G O2 sensor if OEM equipment is desired. If that is something you want to consider, the harness connector must be changed to match the sensor. That connector can be had here: NMWP4F-B

Due to a lack of good, new supply of this original connector, I went ahead and took the above advice and swapped to a 2G connector to utilize the 2G O2 sensor. In order to do so, the wire positions will slightly change. The wire pin orientation in the original connector, as noted in the picture, is as follows with the latch mechanism on the top of the connector and looking at the harness connector from the wire side of the the connector:
[xx]
[01][02]
[03][04]

Original 1G Wiring Positions
01 - White (To ECU)​
02 - Little Black (Thermistor / Heater Ground)​
03 - Red (Power)​
04 - Big Black (Sensor Ground)​

New Wire Positions to Match 2G Sensor
01 - Red (Power)​
02 - Little Black (Thermistor / Heater Ground)​
03 - Big Black (Sensor Ground)​
04 - White (to ECU)​

You must be logged in to view this image or video.
 
Last edited:
B-29: Engine Coolant Temperature Gauge Unit

This is just a single spade connector. Out of three harnesses I have, this has been broken off of each one. It runs to number 4 in the diagram provided.

A new connector can be sourced here: CON-1P250SENDER versions A, B, or C.

You must be logged in to view this image or video.
 

Attachments

  • B29_EngineCoolantTemperatureGaugeUnit1.jpg
    B29_EngineCoolantTemperatureGaugeUnit1.jpg
    23.3 KB · Views: 515
Last edited:
B-30: Engine Coolant Temperature Sensor (for ECU)

This runs to number 5 in the following diagram.

Connector available at: CON-1GECT.

You must be logged in to view this image or video.
 

Attachments

  • B30_EngineCoolantTemperatureSensor1.jpg
    B30_EngineCoolantTemperatureSensor1.jpg
    24.6 KB · Views: 910
Last edited:
B-31: Engine Coolant Temperature Switch (for A/C)

This is for number 6 in the diagram provided.

Connector available at CON-ACTEMP

You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.
 
Last edited:
B-32: Crank Angle and Top Dead Center Sensor (Cam Angle Sensor, CAS)

The 1990 CAS has a built in harness that tails back to this connector on the firewall. On later models, the harness connects directly to the sensor.

The 1990 sensor side CAS connector is available at: NMWP 4P Male.

The 1990 harness side CAS connector is available at: NMWP 4P Female.

You must be logged in to view this image or video.


In other words:
Pin 1- thick black, sensor ground
Pin 2 - red, sensor power
Pin 3 - white, top dead center sensor signal
Pin 4 - black, crank angle sensor signal

Now, the below is the sensor side wiring. Again, note that these wire colors are as if you are looking at the BACKSIDE of the connector on the sensor pigtail.

You must be logged in to view this image or video.


Fold these two over on each other to get the correct wiring.
Harness side to Sensor side
  • Thick black to black
  • Red to red
  • White to white
  • Thin black to yellow
 
Last edited:
C-56: Oxygen Sensor Check Connector

Connector available at: DSD01 F.
 

Attachments

  • C56_OxygenSensorCheckConnector21.jpg
    C56_OxygenSensorCheckConnector21.jpg
    28 KB · Views: 562
Last edited:
C-57: Control Wiring Harness and Body Wiring Harness Combination (1-pin, passenger side kick panel)

Connector available at: 1G 312 F
 

Attachments

  • C57_ControlHarnessAndBodyHarnessCombination21.jpg
    C57_ControlHarnessAndBodyHarnessCombination21.jpg
    26.3 KB · Views: 496
Last edited:
C-58: Control Wiring Harness and Body Wiring Harness Combination (16-pin, passenger side kick panel)

One of two interior connectors that will require modification if the 1990 harness is swapped into a 1991+ car or vice versa. A 1990 harness has a 16-pin connector and fills up every slot. The later models switched to a 18-pin connector (see pin-out here).

The second and third picture show a 1991+ connector transferred onto a 1990 vehicle which was undergoing a turbo swap with a '91 engine, manual harness, and ECU. Note, first, that this is the female end. Secondly, that the two end pin locations are empty; the pins/wires were swapped directly to the '91 connector to the exact location from which they were located on the '90 harness.
 

Attachments

  • C58_ControlHarnessAndBodyHarnessCombination21.jpg
    C58_ControlHarnessAndBodyHarnessCombination21.jpg
    37.1 KB · Views: 713
  • Harness_and_GaugeClusters002.jpg
    Harness_and_GaugeClusters002.jpg
    39.7 KB · Views: 492
  • Harness_and_GaugeClusters014.jpg
    Harness_and_GaugeClusters014.jpg
    34.1 KB · Views: 530
Last edited:
C-59: Control Wiring Harness and Body Wiring Harness Combination (6-pin, passenger side kick panel)

See the C-59 pin-out here. Note that pin 6, the black with green, switches to black with white on the mating connector in the body harness.

Connector available at: DSD06 F.
 

Attachments

  • C59_ControlHarnessAndBodyHarnessCombination31.jpg
    C59_ControlHarnessAndBodyHarnessCombination31.jpg
    35.7 KB · Views: 526
Last edited:
C-63: MPI Control Relay

Connector available at: CON-1GMPI.
 

Attachments

  • C63_MPIControlRelay1.jpg
    C63_MPIControlRelay1.jpg
    33 KB · Views: 493
Last edited:
C-64: MPI Control Unit (ECU, small connector)

Use this to relate wire colors to ECU function: 1G ECU Pin-Out.

The 1G ECU connectors are available at: 1G ECU Set

ERROR: I will get to fixing this eventually, but the "green" wire on pin 105 is actually ORANGE.
 

Attachments

  • C64_MPIControlUnit1.jpg
    C64_MPIControlUnit1.jpg
    33.5 KB · Views: 443
Last edited:
C-65: MPI Control Unit (ECU, medium connector)

Use this to relate wire colors to ECU function: 1G ECU Pin-Out.

The 1G ECU connectors can be sourced here: 1G ECU Set
 

Attachments

  • C65_MPIControlUnit1.jpg
    C65_MPIControlUnit1.jpg
    36.9 KB · Views: 341
Last edited:
**C-66: MPI Control Unit (ECU, large connector)

Note the wire colors of pin 6 (green) and 14 (green w/ white). The green with white stripe wire in all turbo applications runs to pin 1 of the air flow sensor (A-36); this pin slot will be empty in non-turbo models. The green is for the idle, or closed throttle, position switch, which is pin 4 of the throttle position sensor connector on the 1990 (B-02 & B-05) and its own single wire connector on 1991+ models. Information on how to swap 1G ECU pins can be found here: How to remove/replace pins in harness connectors

Use this to relate wire colors to ECU function: 1G ECU Pin-Out.

The 1G ECU connectors can be sourced here: 1G ECU Set
 

Attachments

  • C66_MPIControlUnit1.jpg
    C66_MPIControlUnit1.jpg
    34.4 KB · Views: 468
Last edited:
**C-67: Control Wiring Harness and Body Wiring Harness Combination (under center console)

When swapping this harness into a 1991-1994 1G, this connector will not match up. The 1990 car uses an 8-pin, 7-wire connector. Later manual transmission 1G cars have a 14-pin connector (see manual connector pin-out and a visual) where the later automatic 1Gs have an 18-pin connector (see auto connector pin-out).

Also see these for a visual on where this connector is accessed inside the vehicle:
Cant find were this clip goes. Help!
Harness swap difficulties.
gutting harness is this the c-67 connector?

The second picture shows a '91+ manual connector that was transferred into a 1990 vehicle which was undergoing a turbo conversion with a '91 engine, harness, and ECU. Note that this connector is shown with the foam shroud around it. For this particular connector pair, this is representative of the connector on the dash harness side, not the engine harness side. The third picture is the 1991 connector on the engine harness (i.e., no foam shroud).

The below is the pin-out for the various 1990 model variations.

1 -
M/T - NONE
A/T ONLY - YW, yellow with white, Power/Economy Change Over Switch pin 1 to TCU pin 9
2 -
M/T - RB, red with black, magnetic clutch relay pin 2 to ECU pin 65
A/T - Br, Brown, Accelerator Pedal Switch pin 1 to TCU pin 8
3 -
M/T - RB, red with black, fuse 19 to ECU pin 103 for battery back-up
A/T - RB & RW, red with black (male side) and red with white (female side)
  • w/ Cruise Control - Auto Cruise Control Unit pin 13 to TCU pin 2
  • w/o Cruise Control – Over Drive Switch pin 4 to TCU pin 2
4 -
M/T - 2.0L Turbo ONLY - BR, black with red, Boost Gauge (gauge cluster pin 6) to ECU pin 3
A/T - 2.0L – RG, red with green, Check Engine Light to ECU pin 64
5 -
M/T - LR, blue with red, fuse 3 to Power Window Relay pin 4
A/T - RB, red with black, Magnetic Clutch Relay pin 2 to ECU pin 65
6 -
M/T - Y, yellow, Self Diagnosis Check Connector pin 1 to ECU pin 1
A/T - RB, red with black, Fuse 19 to TCU pin 56 to ECU pin 103
7 - M/T ONLY - W, white, Self Diagnosis Check Connector pin 10 to ECU pin 2
8 -
M/T - RG, red with green, check engine light to ECU pin 64
A/T - YR, yellow with red, Self Diagnosis Check Connector pin 6 to TCU pin 19

The below are A/T only. The M/T connector has only the 8 pin slots.
9 - NONE
10 - LB, blue with black, fuse 7 to Inhibitor Switch pin 4 and TCU pin 11 and, LR, blue with red, to Auto Cruise Control Unit pin 6 on equipped vehicles
11 - NONE
12 - LR, blue with red, fuse 3 to Power Window Relay pin 4
13 - Y, yellow, Self Diagnosis Check Connector pin 1 to ECU pin 1
14 - W & YG, white on check connector side, yellow with green on connector side, changes back to white at ECU; Self Diagnosis Check Connector pin 10 to ECU pin 2


So, if one was to swap a '91+ manual connector onto a '90 harness for use in a '91+ manual vehicle, the wires would be repinned as such:
'90 -> '91+
2 -> 4
3 -> 5
4 -> 9
5 -> 10
6 -> 11
7 -> 12
8 -> 13​
 

Attachments

  • C67_ControlHarnessAndBodyHarnessCombination1.jpg
    C67_ControlHarnessAndBodyHarnessCombination1.jpg
    36.7 KB · Views: 547
  • 90Modified_Harness_Connectors001.jpg
    90Modified_Harness_Connectors001.jpg
    35.3 KB · Views: 524
  • 90Modified_Harness_Connectors005.jpg
    90Modified_Harness_Connectors005.jpg
    42.4 KB · Views: 518
Last edited:
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top