838442 Volvo.Penta Delivery valve

Troubleshooting the electronic ride/fan control system requires additional information from the machine Service Manual. The Electrical System Schematic and the Operation & Maintenance Manual are required support material.As a guide, a typical schematic for the ride/fan control system is at the end of this manual. For a complete schematic, see the Electrical System Schematic in the machine Service Manual.When the troubleshooting procedure instructs to REPAIR THE HARNESS, use the Electrical System Schematic in the machine Service Manual to trace the circuit. Perform continuity checks at connectors to locate harness failures. At component connectors, always check the ground circuit. Less than 5 ohms of resistance is required between the connector ground contacts and frame ground. Excessive ground resistance, greater than 5 ohms, can cause incorrect diagnosing of problems.During troubleshooting, inspect all component and harness connections before any component is replaced. If these connections are not clean and tight they can cause electrical problems, either permanent or intermittent (come and go). Make sure the connections are tight before other tests are made.Failure of an electrical component can cause or be caused by the failure of one or more other components. Always attempt to find and correct the cause of electrical system failure before replacing a component.
Caterpillar Digital MultimeterUse the 6V7070 Digital Multimeter or equivalent for making continuity checks, resistance measurements or voltage measurements. The optional 8T3224 Needle Tip Group for the 6V7070, is useful during troubleshooting. For instruction on use of the 6V7070, see Special Instruction SEHS7734. Continuity testers (such as 8T0500), or voltage testers (such as 5P7277) are not recommended for use on present-day Caterpillar electrical circuits, except for harness tests.The service connector provides access to the service and clear inputs. Connector contact 1 is the service input and contact 2 is the clear input. The service connector is located near the control. For a more exact service connector location and connector requirements, see the Electrical System Schematic in the machine Service Manual.Diagnostic Summary
Various diagnostic functions require the grounding and/or opening of the service and clear contacts at the service connector. During troubleshooting, it is necessary for the service person to make the proper electrical connections between the contacts of the service connector. These electrical connections may be made with two jumpers. Also see the topic Service Box in the Testing And Adjusting section. The same diagnostic information is shown on the computerized monitoring system (CMS). Troubleshooting of ride/fan control system faults can be done through CMS. When using CMS for troubleshooting, all faults associated with the ride/fan control have a MID of 73. For more information, see service manual SENR5247 "Computerized Monitoring System (CMS) With VFD Circular Gauges".Service Box
Service BoxA service box is helpful for the service person to make the proper electrical connections at the service connector during troubleshooting. A service box and wiring diagram is shown in the Service Box illustration. Two connectors are wired in parallel so that the service box is usable on the different types of machine harnesses. To fabricate the service box, the required components are:(1) Clear switch: one 8D2676 Switch.(2) Scroll switch: one 8D2676 Switch.(3) Mode select switch: one 7N8009 Switch.(4) Sure-Seal® connector: one 7N8205 Plug, two 7N7779 Sockets, two 7N7780 Pins.(5) DT® connector: one 3E3373 Plug, four 8T8730 Sockets.(6) Enclosure: locally obtained.(7) Eighteen or sixteen gauge wire: locally obtained.(8) Grommet: locally obtained.Actuating the mode switch scrolls through the two display modes. Actuating the scroll switch scrolls the display with the control in service mode. Actuating the clear switch clears the fault being continuously shown (on hold) when in service mode. instead of having to make a service box, the 9U6665 Service Tool is available. The service tool works similar to the service box.Changing Modes
Ride/Fan Control Display
(1) Readout. (2) Fault present indicator (red). (3) Service mode indicator (yellow). (4) Power indicator (green).The ride/fan control has two display modes. The different modes are identified by the mode number which is shown on readout (1). The display modes are: * Mode 0 - Normal Mode* Mode 1 - Service ModeProcedure
1. Turn key start switch ON. Wait for the Self Test to finish; approximately two seconds.2. At the same time, ground the service and clear contacts of the service connector. This causes the mode numbers to scroll on readout (1). Each time "-0-." is shown, the scrolling stops. The service and clear contacts must be opened from ground, then closed to ground, to scroll the modes again.3. When the desired mode number is shown on readout (1), remove ground from (open) the service and clear contacts.Detected Faults
Initial Troubleshooting Procedure
Ride/Fan Control Display
(1) Readout. (2) Fault present indicator (red). (3) Service mode indicator (yellow). (4) Power indicator (green).When the control detects a fault, the corresponding CID and FMI are shown on readout (1) of the display. Service mode (mode 1) allows for troubleshooting and clearing of each detected fault. For detailed information, see the topic Service Mode (Mode 1) in the Systems Operation section.Use the following procedure for troubleshooting a detected fault. When a fault is detected, the readout will show the fault.1. Enter service mode (mode 1).2. The CID and FMI for the first fault are shown on readout (1) and the fault is on-hold at this time. The display shows "---.", when no fault has occurred.3. To see all detected faults, scroll the faults. To do so, ground the service contact of the service connector.4. Place the desired fault on-hold (stop the scrolling). To do so, remove ground from the service contact of the service connector when the desired fault is shown.5. Observe fault present indicator (2):* If fault present indicator (2) is ON, the fault shown is currently present.* If fault present indicator (2) is OFF, the fault shown is not present at this time. The fault has occurred and then went away, sometime in the past (intermittent).6. To troubleshoot the fault, go to the procedure with that CID and FMI. A general method to locate intermittent faults is to wiggle the related wiring while a helper watches the status of fault present