973875 Volvo.Penta Hexagon screw

Illustration 1 g00956630
Schematic for ECM battery circuit
Illustration 2 g00781787
Terminal locations for ECMTest Step 1. Inspect Electrical Connectors And Wiring.
Thoroughly inspect ECM machine harness connector J1/P1, the battery connections 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:
Unswitched +Battery (terminals 48, 52, and 53)
−Battery (terminals 61, 63, and 65)
Keyswitch (terminal 70)
Check the ECM connector (allen head screw) for the proper 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 are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasions, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK, Troubleshooting a 168-02 Code - Proceed to Test Step 2.
Not OK - There is a problem with the connectors or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.STOPTest Step 2. Check the Battery Voltage at the ECM.
Disconnect machine harness connector P1 from ECM connector J1 and insert a 70-Terminal breakout T.
Illustration 3 g00781870
ECM breakout T-connector
Measure the voltage between P1:48 (unswitched +Battery) and P1:61 (-Battery).
Measure the voltage between P1:52 (unswitched +Battery) and P1:63 (-Battery).
Measure the voltage between P1:53 (unswitched +Battery) and P1:65 (-Battery).
Turn the keyswitch to the ON position.
Measure the voltage between P1:70 (keyswitch) and P1:63 (-Battery).Refer to Illustration 3 for the ECM breakout T-connector.Expected Result:The measured voltage is between 23.0 VDC and 25.5 VDC with no suspected intermittent problems at this time.Results:
OK - The ECM is receiving the correct voltage. Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Battery Voltage is out of range - Proceed to Test Step 3.
Intermittent Or No Voltage - Proceed to Test Step 4.
Keyswitch Voltage Out Of Range - Repair: Trace the wiring for the keyswitch from the ECM through the keyswitch circuit to the batteries. Find the problem and repair the problem. Check the circuit protection for the circuit and for the wiring. Refer to the service manual for instructions on troubleshooting the circuit for the keyswitch.Verify that the repairs eliminate the problem.STOPTest Step 3. Check The Batteries.
Measure no-load battery voltage at the battery posts.
Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure".Expected Result:The measured voltage is at least 23.0 VDC.Results:
OK - Repair: Refer to the service manual for instructions on troubleshooting the machine wiring harness. Troubleshoot the machine wiring harness and repair the machine wiring harness, as required. Verify that the repairs eliminate the problem.STOP
Not OK - Repair: Recharge or replace the faulty batteries. Verify that the repair eliminates the problem.STOPTest Step 4. Use the Bypass Harness for Cat ET 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 both of the 20 amp in line fuses have been removed from the +Battery line. If the fuses are not removed before connection to the battery, a spark may result.
Illustration 4 g01053306
Bypass harnessNote: This bypass harness is only for test applications. This bypass harness may be left only temporarily on the vehicle. The bypass harness can be used in order to determine if the cause of the intermittent problem is interruptions in battery power to the ECM or in the keyswitch circuit.
Turn the keyswitch to the OFF position.
Disconnect machine harness connector J1/P1 from the ECM.
Connect a bypass harness to ECM connector J1.
Remove the two 20 Amp in-line f