Main Relay (Computer/Fuel System): Testing and Inspection

TESTING PROCEDURE:

NOTE: While trouble shooting, always check the wiring, fuses and connectors for good condition and routing. Also check ground locations for good connection. Use the wiring diagrams found in SCHEMATIC DIAGRAMS to supplement your testing efforts.

Color Code Legend:

Checking ECU Ground Connections:

1. Turn ignition OFF.
2. Access fuel injection ECU by removing the passenger side kick panel and glove compartment.
3. Check fuel injection ECU ground connections. They should make good contact and fit tight.

Removing ECU Connector:

4. Remove the ECU connector by pressing up the latch and folding out the wire cluster.

Removing Protective Cover:

5. Remove connector protective sleeve.
CAUTION: ^ Never check connections from the front. Connectors can get damaged and worsen the problem.
^ Check connections through the holes in the connector.
^ Connection pin numbers are printed on the connector side.

Checking System Relay:

6. To check the [1][2]system relay connect a voltmeter between ground and ECU connector pin 9.
7. Connect a lead between ground and ECU connector pin 21. The relay should now close and the voltmeter should show:

Reading: approx. 12 volts

If reading is no or low voltage, check fuse #31 (located behind driver side kick panel), battery, wiring to battery and connectors.
a. If fault found, repair as needed and retest.
b. If no fault found, proceed with next step.

Checking System Relay (Fuel Pump):

8. Check fuel pump relay (part of [1][2]system relay) by connecting a lead between ground and pin 17.
9. Pump relay should close and run fuel pumps.
a. If fuel pumps start operating, relay is O.K.. Proceed with step 10.
b. If fuel pumps don't run, check voltage at terminal #10 of 35-pole connector (located at right side A-post).

Reading: approx. 12 volts

If O.K., check wiring from terminal #10 of 35-pole connector to fuel pumps. Repair as needed.
If reading is incorrect, check relay wiring, fuses and connectors. Repair or replace as necessary.
If wiring, fuses and connectors are in good condition, replace [1][2]system relay and retest.

Assemble Connector:

10. Disconnect the test equipment. Reconnect the ECU and all other connectors, install the kick panel and glove compartment.