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