874370 Volvo.Penta Potentiometer

Illustration 1 g00751534
Schematic
Breathing ether vapors or repeated contact of ether with skin can cause personal injury. Personal injury may occur from failure to adhere to the following procedures.Use ether only in well ventilated areas.Do not smoke while changing ether cylinders.Use ether with care to avoid fires.Do not store replacement ether cylinders in living areas or in the operator's compartment.Do not store ether cylinders in direct sunlight or at temperatures above 49 °C (120 °F).Discard cylinders in a safe place. Do not puncture or burn cylinders.Keep ether cylinders out of the reach of unauthorized personnel.To avoid possible injury, be sure the brakes are applied and all controls are in Hold or Neutral when starting the engine.
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect ECM connector J1/P1, machine connector J3/P3, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Inspect the following components for damage, corrosion, and incorrect attachment:
Battery posts
Alternator
Breaker
Engine ground
Chassis groundExpected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points. All connections and grounds should be tight and free of corrosion.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 2. Check the Starting Aid Switch Status on ET
Remove the ether canister from the ether solenoid.
Connect ET to the service tool connector.
Turn the keyswitch to the ON position.
Press the starting aid switch to "MANUAL". Observe the "Starting Aid Switch Status" on ET.Expected Result:When the starting aid switch is pressed, ET should display the status of the starting aid switch as ON.When the starting aid switch is not pressed, ET should display the status of the starting aid switch as OFF.Results:
OK - The starting aid switch is operating correctly. Proceed to Test Step 6.
Not OK - The ECM is not properly reading the signal from the starting aid switch. Proceed to Test Step 3.Test Step 3. Check the Resistance of the Relay
Illustration 2 g00743796
Connector for the ether relay
Turn the keyswitch to the OFF/RESET position.
Disconnect the wires at terminal 85 (Ether ON) and terminal 86 (Solenoid Return) at the ether relay.
Measure the resistance across terminal 85 (Ether ON) and terminal 86 (Solenoid Return).
Reconnect the wires to the ether relay.Expected Result:The resistance should be between 250 Ohms and 500 Ohms.Results:
OK - Proceed to Test Step 4.
Not OK - The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem. Stop.Test Step 4. Short the Switch Wires
Remove wire F720-GN (Starting Aid Switch) and wire 998-BR (Digital Return) from the starting aid switch.
Short wire F720-GN (Starting Aid Switch) to wire 998-BR (Digital Return).Expected Result:When the wires are shorted, ET should display the status of the starting aid switch as ON.When the wires are not shorted, ET should display the status of the starting aid switch as OFF.Results:
OK - The starting aid switch is not operating correctly.Repair: Replace the starting aid switch.Verify that the repair eliminates the problem. Stop.
Not OK - The starting aid switch is operating correctly. Proceed to Test Step 5.Test Step 5. Short the Switch Inputs at the ECM
Illustration 3 g00743804
J1/P1 breakout
Turn the keyswitch to the OFF position and install a 7X-1715 Adapter Cable (40 Pin Breakout) at ECM connector J1/P1.
Turn the keyswitch to the ON position.
Use a suitable piece of wire to short P1:25 (Starting Aid Switch) and P1:29 (Digital Return) at the breakout.
Observe the results on the "Status" screen of ET.Expected Result:When the wires are shorted, ET should display the status of the starting aid switch as ON.When the wires are not shorted, ET should display the status of the starting aid switch as OFF.Results:
OK - There is a problem in the wiring between the switch and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.
Not OK - The ECM is not reading the switch input properly.Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.Verify that the repair eliminates the problem. Stop.Test Step 6. Check the Resistance of the Ether Solenoid
Disconnect ether solenoid connector J37/P37.
Measure the resistance between J37:1 (Solenoid Power) and J37:2 (Solenoid Return).Expected Result:Resistance should be less than 10 Ohms.