Powertrain Chart 2, Pcm Power & Ground Check
Battery voltage is present at all times at PCM terminals No. 2C4 and 2D4 through circuit No. 840 from engine compartment fuse block, fuse B13. PCM is also fed IGN 1 (hot in run, bulb test and start) at PCM terminal No. 2D5 through circuit No. 539 from engine compartment fuse block, fuse A9. PCM needs both battery and IGN 1 voltage to operate.
PCM grounding points are at PCM terminals No. 2C2, 2C3, 2D2 and 2D3 through circuit No. 451 to ground (circuit G102).
NOTE:
Test numbers refer to numbers on diagnostic chart.
- This test checks for data line codes that would indicate that entire data line is down.
- Checks for battery voltage on circuit No. 840. If voltage is measured at one terminal and not other, check circuit No. 840 for an open to connector C205. If voltage is not measured at either terminal, check fuse B13 and circuit No. 840 to C205 for an open.
- Checks circuit No. 539 and fuse A9 for open.
- Checks for open circuit at circuit No. 451. If voltage measures greater than .1 volt on 1-3 wires, repair open to circuit S234. If voltage measures greater than .1 volt on all 4 wires, repair open from circuit S234 to G102 (ground).
- Checks for an open in circuit No. 451 or inside PCM.
- Checks if data line is open or shorted to ground or voltage, causing a PCM problem.