Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1990 Ford Bronco II RWD, Standard, M5OD-R1FACTORY OEM SERVICE PROCEDURE
Test QB - Introduction
NOTE:
Perform this test when directed by other test procedures. This test is intended to diagnose only the following components or systems:
- ECA
- Harness circuits (PWR GND, VPWR, KAPWR, IGNITION)
TEST PIN WIRE COLOR IDENTIFICATION
| Application (Test Pin No.) | Wire Color | |
|---|---|---|
| Pin 1 (KAPWR) | ||
| 2.3L OHC, 5.0L MA, 5.0L PFI (Truck), 4.9L, 5.8L, 7.3L Diesel, & 7.5L E-Series Van | Black/Orange | |
| 2.3L (Ranger), 2.9L (Bronco II & Ranger) & 4.0L (Ranger) | Yellow/Black | |
| All Others | Yellow | |
| Pin 40 or 60 (PWR GND) | ||
| 4.9L, 5.0L, 5.8L, (Bronco & F-Series), 7.3L Diesel & 7.5L (F-Series) | Black/White | |
| All Others | Yellow | |
| Pin 37 or 57 (VPWR) | Red | |
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.