PCM Power & Ground Check

PCM Power And Grounds:

Circuit Description
The PCM is fed battery voltage at all times at PCM connector C1 terminals 20 and 61 through CKT 1642 from the 20 amp fuse. IGN 1 voltage, Hot in Run, Bulb Test or Stan, is fed through CKT 439 and 10 amp fuse to PCM connector C1 terminals 16 and 19 and C2 terminal 37. The PCM needs all of these inputs to function properly.

The PCM also has four grounding pins: at terminals 21 and 60 of both PCM connectors C1 and C2. These terminals are grounded through CKT 451 to ground G1OO.

Diagnostic Aids
Ensure that the battery is fully charged and tested before performing this check.


Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.

2. Checking battery power supply to the PCM.

7. Checking Ignition 1 and Ignition Supplement voltage to the PCM.

9. Checking ground supply to the PCM. If PCM grounds are good, perform the Powertrain Ground Check to diagnose other vehicle grounds that may cause driveability complaints.