Diagnostic Aids

Circuits are identified in all capital letters (acronyms). For example, Profile Ignition Pickup is identified as PIP. Manufacturer's breakout box overlay test terminals are identified by a "J" prefix. For example, J31 (PIP). The J31 indicates that the measurement is to be taken at terminal No. 31 at the breakout box. The (PIP) indicates that the Profile Ignition Pickup circuit is being checked.

When the letter "I" follows the circuit identification, it implies that the measurement is being taken at the ICM. For example, J31 (PIP I). The (PIP I) implies that the measurement is of the PIP circuit at the ICM.

When the letter "S" follows the circuit identification, it implies that the measurement is being taken at the Crankshaft Position Sensor (CKP). For example, J32 (CKP+ S). The (CKP+ S) implies that the measurement is of the CKP sensor positive circuit at the CKP sensor. When the letter "C" follows the circuit identification, it implies that the measurement is being taken at the coil. For example, J10 (C3C). The (C3C) implies that the measurement is of the C3 circuit at the coil pack.

The following information should also be noted during testing:

• When checking a wiring harness, perform both a visual inspection and a continuity test. Inspect terminal connector pins for damage, bending, spreading and corrosion when directed to remove a connector.
• Spark timing adjustments are not possible. Timing is controlled by ICM with input from PCM.
• When checking voltage drop to GROUND, circuit must have a voltage drop of less than one volt.
• Battery voltage (VBAT) is any voltage reading within 2 volts of actual battery voltage.
• EEC-IV Breakout Box (T83L-50-EEC-IV) connected to EI diagnostic cable is referred to as breakout box or EI breakout box. If a second breakout box is connected to PCM wiring harness connector, it will be referred to as second or PCM breakout box. This setup allows testing of EI components and wiring harness circuits.