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Home >> Lincoln >> 1995 >> Mark VIII V8-4.6L DOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Pinpoint Tests >> XB - Variable Control Relay Module (VCRM) >> XB2 - PCM Ground Fault Isolation
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XB2 - PCM Ground Fault Isolation



- Key "OFF".

- Breakout box installed, Powertrain Control Module (PCM) connected.

- Measure voltage between B(+) post of the battery and SIG RTN (GY/R wire) in the Data Link Connector (DLC).

- Is voltage greater than 10.5 volts and within 1.0 volt of the reading in XB1?

Yes -- Go to XB10 (PCM ground circuits OK). XB10 - Check VPWR Circuit Continuity Between PCM and VCRM

No -- Go to XB3 (to check PCM ground circuits). XB3 - Check SIG RTN Continuity
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