5032058 JOHNSON BUSH

Illustration 1 g01331516
Schematic of the power supply (31 pin MIC)
Illustration 2 g01331519
Schematic of the power supply (70 pin MIC)
Batteries give off flammable fumes which can explode.To avoid injury or death, do not strike a match, cause a spark, or smoke in the vicinity of a battery.
Test Step 1. Check The Batteries
Measure no-load battery voltage at the battery posts.
Load test the batteries.Note: The batteries must pass the load test. The minimum voltage must be 11.5 Volts DC for a 12 Volt battery. If the battery voltage of a 12 Volt battery is below 12.4 Volts DC, the battery must be charged.Expected Result:The batteries provide sufficient voltage.Results:
OK - Proceed to Test Step 2.
Not OK - Recharge or replace the batteries. Verify that the repair eliminates the fault.STOPTest Step 2. Inspect Electrical Connectors And WiringNote: If the system has a 31 pin MIC, pins P1:57 and P1:69 are not used.
Illustration 3 g01625208
ECM pin locations
(56) Battery +
(57) Battery +
(68) Battery -
(69) Battery -
(70) Keyswitch
Thoroughly inspect the harness connector J1/P1. Also inspect the connections for the battery and the connections to the keyswitch. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the following connections:
P1:56 and P1:57 (Battery +)
P1:68 and P1:69 (Battery -)
P1:70 (Keyswitch)
Check the ECM connector (Allen head screw) for the correct torque of 6.0 N m (55 lb in).
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM. Also, check the harness and wiring for abrasions and for pinch points from the keyswitch to the ECM. Expected Result:All connectors, pins, and sockets should be completely coupled and/or inserted. The harness and wiring should be free of corrosion, abrasion, and/or pinch points.Results:
OK - Proceed to Test Step 3.
Not OK - There is a fault in the connectors or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are correctly installed and ensure that the connectors are completely coupled.STOPTest Step 3. Check the Battery Voltage at the ECMNote: If the system has a 31 pin MIC, pins P1:57 and P1:69 are not used.
Illustration 4 g01625209
Test points for the Breakout T.
(56) Battery +
(57) Battery +
(68) Battery -
(69) Battery -
(70) Keyswitch
Disconnect engine harness connector P1 from ECM connector J1 and insert a 70 Pin Breakout T.
Reconnect the harness.
Turn the keyswitch to the ON position.
Measure the voltage between P1:56 (Battery +) and P1:68 (Battery -).
Measure the voltage between P1:57 (Battery +) and P1:69 (Battery -). Refer to Illustration 4 for the ECM Breakout T-connector.Note: Connections P1:57 and P1:69 are not used on certain installations.Expected Result:The measured voltage is between 11.0 Volts DC and 13.5 Volts DC for a 12 Volt system and between 22.0 Volts DC and 27.0 Volts DC for a 24 Volt system with no suspected intermittent faults.Results:
OK - Proceed to Test Step 4.
Not OK - Repair: If the ECM is not receiving the correct voltage and an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect". Repair any damaged connectors or damaged wiring and/or replace any damaged connectors or damaged wiring. Verify that the repairs eliminate the fault and then proceed to Test Step 4.If the voltage at the keyswitch is out of the nominal range, trace the wiring for the keyswitch from the ECM through the keyswitch circuit to the batteries. Identify the fault and repair the fault. Check the circuit protection for the circuit and for the wiring.Verify that the repairs eliminate the fault.STOPTest Step 4. Use the Bypass Harness for the Electronic Service Tool to Bypass the Machine Wiring
Batteries give off flammable fumes which can explode.To avoid injury or death, do not strike a match, cause a spark, or smoke in the vicinity of a battery.
Do not connect the bypass harness to the battery until the 20 Amp in-line fuse has been removed from the battery+ line. If the fuse is not removed before connection to the battery, a spark may result.