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.
2001 Ford Mustang Base, 2D Convertible, AutomaticFACTORY OEM SERVICE PROCEDURE
Test A: No Communication With Generic Electronic Module
- Turn ignition switch to RUN position. Measure voltage between ground and input side of Central Junction Box (CJB) fuses No. 32 (15-amp) and No. 39 (5-amp). CJB is located behind left side of instrument panel, left of steering column. See Fig 1 and Fig 2 . If battery voltage exists at both terminals, go to next step. If battery voltage does not exist at either terminal, repair power distribution circuit to appropriate fuse as necessary. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Ensure fuses No. 32 and 39 are installed. Turn ignition switch to LOCK position. Disconnect 4-pin Generic Electronic Module (GEM) harness connector C291. GEM is located behind left side of instrument panel, next to CJB. Measure voltage between ground and GEM harness connector C291 terminal No. 1 (White/Yellow wire). See Fig 3 . If battery voltage exists, go to next step. If battery voltage does not exist, repair open in White/Yellow wire between GEM and fuse No. 39. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Disconnect 26-pin GEM harness connector C352. Turn ignition switch to RUN position. Measure voltage between ground and GEM harness connector C352 terminal No. 22 (Black/Pink wire). See Fig 4 . If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Black/Pink wire between GEM and fuse No. 32. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
- Turn ignition switch to LOCK position. Measure resistance between ground and GEM harness connector C291 terminal No. 2 (Black/White wire). If resistance is 5 ohms or less, repair module communication concern. See MODULE COMMUNICATIONS NETWORK - MUSTANG article. If resistance is more than 5 ohms, repair open in Black/White wire between GEM and ground. Ground point is located behind center of instrument panel. See GROUND DISTRIBUTION article in WIRING DIAGRAMS.
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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.