System Circuit Inspection

SYSTEM CIRCUIT INSPECTION
^ Most intermittent malfunctions are caused by faulty electrical connections or wiring. Perform careful check of suspect circuits for:

A. Poor mating of connector halves, or terminals not fully seated into the connector body (backed out).
B. Improperly formed or damaged terminals. All connector terminals in malfunctioning circuits should be carefully reformed to increase contact tension.
C. Poor terminal to wire connection.

^ Never connect any tester (voltmeter, ohmmeter, etc.) to the Engine Control Module (ECM) when its connectors are disconnected. Attempting to do so may cause damage to the ECM.
^ Be sure to use a digital multimeter whose minimum resistance is more than one megohm per volt. Any other digital multimeter should not be used because accurate measurements are not obtained. (Use J 39200 or equivalent.)
^ When checking voltage at each terminal of the connector which is connected to ECM, be sure to connect negative (-) probe to body ground and, using a jumper wire connect the positive (+) probe to connector terminal being tested. Applying probes of digital multimeter improperly may cause a sensor or ECM to be shorted and damaged.