Test 5 Self Test Not Functional

NOTE: Observe the following instructions when performing the Subroutine Tests.


1. Do not measure voltage or resistance at the MCU module or connect any test light to it, unless otherwise instructed to do so.

2. Turn ignition key off and isolate both ends of a circuit whenever checking for shorts or continuity.

3. Connectors shown in schematics are viewed from front of connector.

4. Disconnect solenoids and switches from harness before checking continuity, resistance or by energizing by applying battery voltage directly.

5. Follow each step in order beginning with the first one in the appropriate routine. Follow each step until the problem is located, then correct the problem and perform the appropriate Functional Test to make sure that the problem has been corrected.

Fig.5 - MCU Wiring Circuit, Inlet Engines:

Test 5-Self Test Not Functional

1. Make sure that Self-Test trigger jumper and voltmeter were properly connected to the correct pins of the Self-Test connector and that a good connection existed.

2. Check power circuit 687 for power with ignition switch in Run position, and ground circuit 60 to MCU for continuity, Fig.5. If fusible link is burned, check for a short circuit in power circuit 687. If circuit 687 is okay, proceed to next step. if not, repair circuit 687.

3. Check circuits 190, 201 and 60 between MCU and Self-Test connector for continuity, and make sure that circuit 190 is not shorted to ground. If circuits are okay, proceed to next step. If not, repair circuit(s).

4. Check TAB solenoid resistance. If resistance is within 50-110 ohms, replace MCU module. If not, replace solenoid.