3858071 Volvo.Penta Engine

Table 1
Diagnostic Codes Table    
Code and Description     Conditions which Generate this Code     System Response    
91-8 Throttle Position Sensor abnormal frequency, pulse width, or period     The Electronic Control Module (ECM) detects an incorrect frequency on the throttle signal or an incorrect duty cycle on the throttle signal. The frequency is below 150 Hz or the frequency in above 1000 Hz. The duty cycle is less than 7 percent or the duty cycle is greater than 95 percent.     The code is logged. The ECM flags the throttle position as invalid data and a default value of zero percent is used. The engine speed is limited to low idle.    
264-8 Deceleration Throttle abnormal frequency, pulse width, or period     The ECM detects an incorrect frequency on the signal for the decelerator position sensor or an incorrect duty cycle on the signal for the decelerator position sensor. The frequency is below 150 Hz or the frequency in above 1000 Hz. The duty cycle is less than 7 percent or the duty cycle is greater than 95 percent.     The code is logged. The ECM flags the signal for the decelerator position sensor as invalid data and the feature is disabled. The ECM will use the throttle position sensor for the desired throttle position.    Throttle Position SensorThe throttle position sensor provides the throttle signal to the ECM. The throttle position sensor is mounted to a throttle lever that allows the operator to control the speed of the engine. The geometry of the throttle lever arm controls both the travel of the sensor and the range of the output signal. The throttle position sensor cannot be adjusted.The output from the throttle position sensor is a PWM signal that varies with the position of the throttle lever. The throttle position sensor produces a minimum duty cycle in the released position and a maximum duty cycle in the full throttle position. When the lever is in the low idle position, the ECM translates the sensor's output signal to a throttle position of 0 percent. When the throttle lever is fully actuated, the ECM translates the output signal to a throttle position of 100 percent.Decelerator Position SensorThe deceleration pedal is used by the operator in order to decrease desired engine speed during operating conditions. The desired engine speed can be controlled by the operator from high idle, down to the "Deceleration Speed Set Point".The scaling factor for the deceleration pedal is calculated by the ECM upon powerup. The scaling factor is also calculated when the "Deceleration Speed Set Point" is changed. If the throttle lever is set below high idle, the deceleration pedal will not have an effect until the pedal has reached the proportional value that is equal to the present desired engine speed that has been set by the throttle lever.Each of the sensors are powered by 8.0 0.4 VDC that is provided by the ECM. A digital return for the sensor is also provided by the ECM.The ECM uses an automatic calibration function that allows the ECM to maximize the usable range of the sensors. The automatic calibration function assumes a range of PWM duty cycle at powerup. If the duty cycle of the sensors exceeds this initial range, the automatic calibration function adjusts the limits of the duty cycle in order to adjust for the new range.
Illustration 1 g01384724
Schematic for the speed controlsTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01214624
Locations of the J1/P1 ECM connectors for the speed controls (typical left side engine view)
Thoroughly inspect the J1/P1 ECM connectors. Also, thoroughly inspect the mechanical condition of the throttle lever and the deceleration pedal. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details that are related to inspecting the connectors.
Illustration 3 g01384735
P1 ECM connector (P1-4) Digital sensor supply (P1-18) Digital return (P1-66) Throttle position (P1-68) Decelerator position
Illustration 4 g01159881
Terminal locations at the connector for the throttle position sensor (Terminal A) Digital sensor supply (Terminal B) Digital return (Terminal C) Throttle position
Perform a 45 N (10 lb) pull test on each of the wires in the circuit.
Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and 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 - The connectors and/or wiring are not OK.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.Verify that the repair eliminates the problem.STOPTest Step 2. Inspect the Throttle Assemblies
Inspect the throttle lever and the decelerator pedal for components that are loose, bent, missing, or worn.
Slowly move the lever and the pedal through the full range of travel of the components.Expected Result:Both the throttle lever and the decelerator pedal operates smoothly without excessive drag.Results:
OK - The throttle assemblies function properly. Proceed to Test Step 3.
Not OK - The throttle lever or the decelerator pedal is in poor repair.Repair: Repair the throttle assemblies or replace the throttle assemblies, as required. Verify that the repair eliminates the original problem.STOPTest Step 3. Check the Status for "Throttle Position" and "Decelerator Position" on Caterpillar Electronic Technician (ET)
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status for "Throttle Position" and "Decelerator Position" on Cat ET while you operate the throttle lever and the decelerator pedal through the entire range of travel.Expected Result:The status is zero percent when the throttle controls are fully retracted. The status progressively increases to 100 percent when the throttle controls are fully actuated.Results:
OK - Both of the throttle position sensors are working properly.Repair: There does not appear