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.
Power Circuits
Turn ignition off. Using a DVOM, check for battery voltage between ground and B+ circuit at PCM terminal No. 55 (104-pin PCM), terminal No. B40 (122-pin PCM), terminal No. B45 (150-pin PCM - Focus 2.3L), or terminal No. A44 or B44 (150-pin PCM - all others). See Fig 1-Fig 4 . Turn ignition switch to START or RUN position. Check for battery voltage between ground and specified VPWR circuit at PCM harness connector. See PCM VPWR CIRCUIT TERMINAL IDENTIFICATION table. If battery voltage is not present, check for an open in VPWR circuit between PCM and PCM power relay. For additional testing procedures, see TEST B: EEC-V POWER RELAY under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.
| Application | (1) PCM Terminal No. | ||
|---|---|---|---|
| Models With 122-Pin PCM | B34 & B46 | ||
| Focus 2.3L With 150-Pin PCM | B35 & B36 | ||
| All Other Models With 150-Pin PCM | A32 & A33, Or B32 & B33 | ||
| All Other Models | 71 | ||
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NO RELATED
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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.