20758137 Volvo.Penta Plug

Illustration 1 g03729581
Schematic diagram for the PTO switches
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 2 g02690278
View of the pin locations on the P1 connector for the PTO switches
(9) PTO mode - OFF
(10) PTO mode - resume
(31) PTO mode - raise
(32) PTO mode - lower
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Check the fuses.
C. Perform a 30 N (6.7 lb) pull test on each wire in the PTO switch connectors and on each wire in the ECM connector that is associated with the PTO switches.
D. Check the harness for corrosion, abrasion, and pinch points from the PTO switches to the ECM and the battery supply.
Damaged wire or connector
Result: A damaged wire or damaged connector was not found. The fuses are OK.
Proceed to Test Step 2.
Result: A damaged wire or damaged connector was found. A fuse is blown.
Repair: Repair the damaged wire or the damaged connector. Replace any blown fuses.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
2. Check for Active Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Check the "Active Diagnostic Codes" screen. Look for an active or recently logged 976-2 diagnostic code.
Diagnostic Trouble Codes
Result: A 976-2 diagnostic code is active.
Proceed to Test Step 3.
Result: A 976-2 diagnostic code is recently logged.
Repair: The logged code may be caused by operating the PTO switches in one of the conditions that are listed in Table 1 or an intermittent fault may exist.
Refer to Troubleshooting, "Electrical Connectors - Inspect" in order to identify intermittent faults.
Result: There is no active or recently logged 976-2 diagnostic code.
If the switches are not operating correctly, an open circuit may exist.
Proceed to Test Step 3.
3. Check the PTO Mode Switches on the Electronic Service Tool
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Observe the status of the PTO switch on the electronic service tool while the PTO on/off switch is cycled.
E. Use the electronic service tool in order to observe the status of the PTO mode switch while the PTO lower/raise switch is cycled.
F. Use the electronic service tool in order to observe the status of the PTO switch while the PTO Resume switch is cycled.
Switch status
Result: The status of each switch changes when the switch is operated.
The fault appears to be resolved. Return the engine to service.
Result: One of the switches indicates "OPEN" even when the switch is pressed.
Proceed to Test Step 4.
Result: One of the switches indicates "CLOSED" even when the switch is not pressed.
Proceed to Test Step 6.
4. Check the Power Supply to the Suspect Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the battery supply wire from the suspect switch.
C. Turn the keyswitch to the ON position.
D. Check the voltage between the battery supply wire to the suspect switch and a suitable ground.
10 V to 14 V
Result: The measured voltage is within the expected range.
Proceed to Test Step 6.
Result: The measured voltage is not within the expected range.
Proceed to Test Step 5.
5. Check the Wiring Between the Suspect switch and the ECM Main Power Relay
A. Turn the keyswitch to the OFF position.
B. Disconnect the battery supply wire from the suspect switch.
C. Disconnect the ECM main relay.
D. Use a multimeter to measure the resistance between the disconnected wire and terminal 87 on the harness connector for the ECM main relay.
Less than 5 Ohms
Result: The measured resistance is greater than 5 Ohms.
The fault is in the wiring between the suspect switch and the ECM main relay
Repair: Check all wiring between the suspect switch and the ECM main relay. Refer to the Electrical Schematic for the application.
Replace the faulty wiring.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: The measured resistance is less than 5 Ohms.
Repair: Refer to Troubleshooting, "Relay - Test (ECM Main Relay)" in order to test the circuit for the ECM main relay.
6. Create at Short Circuit at the Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the suspect switch.
C. Fabricate a jumper wire and install the jumper wire between the two terminals for the switch.
D. Turn the keyswitch to the ON position.
E. Monitor the status screen on the electronic service tool while the jumper wire is being disconnected and reconnected.
Switch status
Result: When the jumper wire is connected, the status of the suspect PTO switch is "CLOSED". When the jumper wire is disconnected, the status of the suspect PTO switch is "OPEN".
Repair: Replace the switch.
Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair has eliminated the problem.
Result: When the jumper wire is disconnected, the status of the suspect PTO switch is "CLOSED".
Reconnect the switch and proceed to Test Step 7.
Result: When the jumper wire is connected, the status of the suspect PTO switch is "OPEN".
Proceed to Test Step 8.
7. Check the Switch Return Wire for a Short Circuit
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the suspect switch. Disconnect the P1 connector from the ECM.
C. Use a suitable multimeter to measure the resistance between the terminal for the suspect switch on the P1 connector and all other terminals on the P1 connector.
Greater than 1 k Ohm
Result: At least one of the resistance measurements is less than 1 k Ohm.
There is a short in the wiring between the suspect switch and the P1 ECM connector.
Repair: Check all wiring between the suspect switch and the ECM. Refer to the Electrical Schematic for the application.
Replace the faulty wiring.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All resistance measurements are greater than 1 k Ohm.
Contact the Dealer Solution Network (DSN).
8. Measure the Resistance of the Switch Return Wire to