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RELAYS—OPERATION/TESTING The following description of operation and tests apply only to the ASD and other relays. OPERATION • Terminal number 30 is connected to battery volt- age. For both the ASD and other relays, terminal 30 • The ECM grounds the coil side of the relay through terminal number 85. • Terminal number 86 supplies voltage to the coil side of the relay. • When the PCM de-energizes the ASD and other relays, terminal number 87A connects to terminal 30. • When the ECM energizes the ASD and other relays, terminal 87 connects to terminal 30. This is TESTING The following procedure applies to the ASD and other relays. (1) Remove relay from connector before testing. an ohmmeter to check the resistance between termi- (3) Connect the ohmmeter between terminals 30 and 87A. The ohmmeter should show continuity (4) Connect the ohmmeter between terminals 87 and 30. The ohmmeter should not show continuity at (5) Connect one end of a jumper wire (16 gauge or smaller) to relay terminal 85. Connect the other end (6) Connect one end of another jumper wire (16 gauge or smaller) to the power side of the 12 volt WARNING: DO NOT ALLOW OHMMETER TO CON- (7) Attach the other end of the jumper wire to relay terminal 86. This activates the relay. The ohm- (8) Disconnect jumper wires. ity and resistance tests. If the relay passed the tests, BOOST / PRESSURE SENSOR If the boost pressure sensor fails, the PCM records a DTC into memory and continues to operate the Fig. 19 Glow Plug Relay Location 1 – MOUNTING BOLT Fig. 20 Boost Pressure Sensor Location 1 – BOOST PRESSURE SENSOR HARNESS CONNECTOR 14 - 34 FUEL SYSTEM—2.5L DIESEL ENGINE XJ DIAGNOSIS AND TESTING (Continued) 2000 JEEP CHEROKEE |