F4
What This Code Means
Little or no battery voltage present at Terminal Connection 87 (Wire 15) on RL1 socket; Little or no battery voltage present at Terminal Connection 86 (Wire 15A) on RL1 socket; Little or no battery voltage present at Terminal Connection 87 (Wire 15) of the Engine Run Relay (RL2).; Utility Failure Engine Cranking; AC Voltage (Low); AC Voltage; DC Voltage during cranking; DC Voltage during engine run condition; Field flash; Governor position; Governor feedback position; Oxygen sensor input/return; CANbus High and Low; Control 5V when ECM active; Control 12VDC - always present; 0VDC-5VDC to ECM ground; Ground control (PCB); Variable 9VDC; 12 VDC not present on Wire 25; Voltage does not appear near 0 VDC on Wire 25 in MANUAL mode; Approximately 12 VDC not measured on Wire 25A at RLY2; Battery voltage not measured on Wire 13 to ground (relay coil or common); Resistance from Wire 608 on the coil of the relay to ground is very high or open; No or low voltage measured on Wire 14D to ground; F4
Possible Causes
- •Wire 15 is pinched or cut
- •Wire 15 is prevented from having proper battery voltage
- •Wire 15A is pinched or cut
- •Wire 15A is prevented from having proper battery voltage
- •Wire 15 is pinched, cut, or in a condition that prevents voltage from being present.
- •Utility Failure
- •Low AC voltage
- •DC Voltage during cranking
- •DC Voltage during engine run condition
- •Field flash
- •Governor position
- •Governor feedback position
- •Oxygen sensor input/return
- •CANbus High and Low
- •Control 5V when ECM active
- •Control 12VDC - always present
- •0VDC-5VDC to ECM ground
- •Ground control (PCB)
- •Variable 9VDC
- •Wire 25 has no continuity
Suggested Actions
- 1Verify that Wire 15 is not pinched or cut or in any other way prevented from having proper battery voltage.
- 2Verify that Wire 15A is not pinched or cut or in any other way prevented from having proper battery voltage.
- 3Verify that Wire 15 is not pinched, cut, or in any other condition that would not allow voltage to be present on Wire 15.
- 4Controller in AUTO
- 5Check Wire 25 for continuity
- 6Repair or replace harness
- 7Verify pin connections to controller
- 8Replace controller
- 9Test RLY2 again
- 10Test the harness back toward the battery looking for a break in the wire
- 11Go to results (implies further troubleshooting steps not provided in text)
- 12Replace F4 fuse
- 13Replace FB4
- 14Repair any wiring between FB4 and coil where necessary
- 15Refer to Test 130, IR Relay Test
- 16Repair wiring
- 17Inspect ECM plug and pins
- 18Replace the ECM
- 19Replace the faulty coil
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