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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSFORD1990RANGER 4WD L4-140 2.3L SOHCREPAIR AND DIAGNOSISTRANSMISSION AND DRIVETRAINTRANSFER CASETESTING AND INSPECTIONELECTRONIC SHIFT DIAGNOSISCONTROL MODULE SELF TEST
1990 Ford Ranger 4WD L4-140 2.3L SOHC
Control Module Self Test
1990 Ford Ranger 4WD L4-140 2.3L SOHCSECTION Control Module Self Test
The Electronic Control Module (ECM) has a diagnostic capability of its internal circuitry. Self test procedure is as follows:
1. Remove the Five-Wire Connector and the Eight Wire Connector from the ECM.
2. Turn ignition switch to the RUN position.
3. Activate the system self-test by pressing and releasing the self-test switch. Note the results as indicated by the indicator light:
NOTE: The self test switch and indicator light are located on the ECM.
a. A FLASHING Indicator Lamp, (approximately one flash per second) indicates that the ECM is functioning properly.
b. A STEADY Indicator Light indicates that the ECM is inoperative and must be replaced.
1. Remove the Five-Wire Connector and the Eight Wire Connector from the ECM.
2. Turn ignition switch to the RUN position.
Control Module Self Test:
3. Activate the system self-test by pressing and releasing the self-test switch. Note the results as indicated by the indicator light:
NOTE: The self test switch and indicator light are located on the ECM.
a. A FLASHING Indicator Lamp, (approximately one flash per second) indicates that the ECM is functioning properly.
b. A STEADY Indicator Light indicates that the ECM is inoperative and must be replaced.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.