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Diagnostic Tests

Fuel feedback system incorporates a diagnostic connector which provides for systematic evaluation of each component that could cause a malfunction. See Fig 2 .

An electronic Fuel Feedback Tester (ET-501) is available to aid in diagnosis. When tester is not available, there are several tests for each system.

To perform a complete system diagnosis, test No. 1 should be performed first and succeeding tests in sequence, thereafter. These tests will provide a thorough system diagnosis.

The steps in each test will provide a systematic evaluation of each component that could cause a malfunction. After completing a repair, repeat the test to ensure malfunction has been eliminated. The equipment required for tests is a tachometer, a hand vacuum pump, a digital volt-ohmmeter (DVOM) with minimum 10-megohm input impedance, and jumper wires. For terminal identification during testing, See Fig 1 and Fig 2 .

Fig 1: 4.2L Engine CEC System Wiring Diagram
G90B15850Courtesy of CHRYSLER MOTORS.
Fig 2: 4.2L Engine Diagnostic, MCU & Wire Harness Connectors
G90C15851Courtesy of CHRYSLER MOTORS.