Test 1 No Start Test

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 1-No Start Test


NOTE: This procedure is only for no start conditions created by the MCU system.


1. Check tach lead circuit 11, Fig. 5 for a short to ground. Leave harness connected to MCU and disconnect coil horseshoe connector and ignition module from harness.

2. Measure resistance of circuit. If resistance is less than 1000 ohms, proceed to step 3. If resistance is greater than 1000 ohms, problem is not in MCU system.

3. To determine fault, disconnect MCU module from harness and again check for short circuit to ground by measuring resistance. If resistance is less than 1000 ohms, repair circuit 11. If resistance is greater than 1000 ohms replace MCU module.