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.
2006 Mercury Mariner 4WD V6-3.0L VIN 1FACTORY OEM SERVICE PROCEDURE
Test B: Powertrain Control Module (PCM) Power Relay
PINPOINT TEST B: POWERTRAIN CONTROL MODULE (PCM) POWER RELAY
This pinpoint test is intended to diagnose the following:
^ harness circuits: PCMRC ISP-R
^ vehicle power
^ ignition start/run
^ PCM power relay ground
^ battery positive voltage
^ PCM power relay (12A646)
^ PCM (12A650)
Note: The IGN START/RUN and ground circuits or the B+ and VPWR circuits may be reversed in the harness connector. Refer to the W~nng Diagrams Manual Electronic Engine Control Cell for schematic and connector information.
B1 - B3:
B4 - B5:
B6:
B7 - B8:
B9 - B10:
B11 - B12:
B13 - B14:
B15 - B16:
B17:
Factory Service Tools
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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.
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