874348 Volvo.Penta Relay

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
544-8
Engine Cooling Fan Speed Sensor : Abnormal Frequency, Pulse Width, or Period The engine speed is equal to or greater than low idle but less than 2400 rpm for one minute.
The fan speed is less than 38 rpm or the fan speed is greater than 2000 rpm for two seconds. The code is logged. The fan speed sensor is an analog sensor that provides a speed signal from the engine cooling fan to the Electronic Control Module (ECM). The ECM controls the speed of the fan by varying the current to the fan speed solenoid. The ECM attempts to keep the fan within 50 rpm of the desired fan speed.The fan speed sensor receives a regulated 5.0 VDC supply voltage from the ECM. The fan speed sensor provides a pulse width modulated signal to the ECM that represents the speed of the fan. The frequency range of the output represents fan speeds from 50 rpm to 1800 rpm.Note: Refer to Troubleshooting, "Sensor Supply - Test" if the ECM has detected a problem with the analog sensor supply voltage.
Illustration 1 g06553012
Schematic for the fan speed sensor
Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING
Turn the keyswitch to the OFF position.
Illustration 2 g01234146
Location of ECM connectors
Thoroughly inspect ECM connector J1/P1, ECM connector J2/P2, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01560419
P1 terminals that are associated with the cooling fan speed
(P1-2) +5 V analog supply
(P1-3) Sensor return
Illustration 4 g01607034
P2 terminals that are associated with the cooling fan speed
(P2-70) Engine fan speed
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the Cat Data Link.
Check the allen head screw on each ECM connector for the proper torque. Also, check the allen head screw on the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. CHECK THE STATUS OF THE ENGINE FAN SPEED WITH CATERPILLAR ELECTRONIC TECHNICIAN (ET)
Turn the keyswitch to the OFF position.
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Access the "Fan Override Test" under the "Diagnostics" menu.
Start the "Fan Override Test" on Cat ET. Set the fan speed to 800 rpm.
Use a 1U-6602 Photo-Tachometer to determine the actual speed of the fan.
Compare the engine fan speed that is reported by Cat ET to the actual engine fan speed that is reported by the photo-tachometer.
Deactivate the "Fan Override Test".
Turn the keyswitch to the OFF position.Expected Result:The actual fan speed is within 50 rpm of the engine fan speed that is reported by Cat ET.Results:
OK - The engine fan speed is within the desired rpm range.Repair: The sensor is operating correctly. There may be an intermittent electrical problem in a connector or in the harness. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The engine fan speed is not within the desired rpm range. Proceed to Test Step 3.Test Step 3. CHECK THE ANALOG SENSOR SUPPLY VOLTAGE AT THE SENSOR CONNECTOR
Disconnect the connector for the engine cooling fan speed sensor.
Turn the keyswitch to the ON position.
Measure the voltage across terminal A (+5 V analog supply) and terminal B (sensor return).
Turn the keyswitch to the OFF position.Expected Result:The analog sensor supply voltage is 5.0 0.5 VDC.Results:
OK - The supply voltage is reaching the sensor. Proceed to Test Step 4.
Not OK - The supply voltage is not reaching the sensor. Proceed to Test Step 6.Test Step 4. CHECK THE SIGNAL FREQUENCY FOR THE ENGINE COOLING FAN SPEED SENSOR AT THE SENSOR CONNECTOR
Turn the keyswitch to the OFF position.
Remove the wire from terminal C (engine fan speed) on the sensor side of the connector for the engine cooling fan speed sensor. Connect the sensor connector.
Turn the keyswitch to the ON position.
Access the "Fan Override Test" under the "Diagnostics" menu on Cat ET.
Start the "Fan Override Test" on Cat ET. Set the fan speed to 800 rpm.
Use a multimeter to measure the frequency between the signal wire from the sensor and engine ground.
Deactivate the "Fan Override Test".
Turn the keyswitch to the OFF position.
Restore all connectors and wiring to the original configuration.Expected Result:The frequency is approximately 13 Hz.Results:
OK - The frequency is approximately 13 Hz. The engine cooling fan speed sensor is generating the correct signal. Return the wire to terminal 1 (engine fan speed) of the connector for the engine cooling fan speed sensor. Proceed to Test Step 5.
Not OK - The frequency is not approximately 80 Hz.Repair: The engine cooling fan speed sensor is not generating the correct signal. Replace the engine cooling fan speed sensor. Verify that the replacement corrects the original problem.STOPTest Step 5. CHECK THE SIGNAL FREQUENCY FOR THE ENGINE COOLING FAN SPEED SENSOR AT THE ECM CONNECTOR
Disconnect the J2/P2 ECM connector. Remove the wire from terminal P2-70 (engine cooling fan speed sensor) at the P2 connector.
Turn the keyswitch to the ON position.
Access the "Fan Override Test" under the "Diagnostics" menu on Cat ET.
Start the "Fan Override Test" on Cat ET. Set the fan speed to 800 rpm.
Measure the frequency between the signal wire from the sensor and engine ground.
Deactivate the "Fan Override Test".
Turn the keyswitch to the OFF position.
Reconnect all connectors and wires.Expected Result:The frequency is approximately 13 Hz.Results:
OK - The frequency is approximately 13 Hz.Repair: Verify that the