Eaton Fuller Advantage (2017) Fault Code: 17 PID: SPN: 1321 FMI: 4 Start Enable Relay: Voltage Below Normal or Shorted Low

Description

Overview:
Vehicles with an Fuller Advantage transmission are required to disable engine cranking when the transmission is in a non-neutral gear position. Some vehicles prevent non-neutral engine cranking through the use of a normally open Start Enable Relay actuated by the Transmission Electronic Control Unit (TECU) to interrupt power to the Starter. Other vehicles require the TECU to send a transmission engine crank enable message over the J1939 Data Link before the engine ECU will allow cranking. The Start Enable Relay circuit is supplied and wired by the OEM. For vehicles equipped with a physical Start Enable Relay circuit, the relay will only latch when the following three conditions exist:
• Driver Interface Device is in the neutral position.
• Transmission has confirmed that it is physically in neutral.
• Engine is not running.

Under these conditions the TECU supplies a voltage source and a ground path to the Start Enable Relay coil, latching the relay. The latched relay allows Engine-Starter engagement when the ignition key is turned to the crank position. If these conditions are not met, the TECU removes the voltage source and ground path to the Start Enable Relay, opening the relay and preventing engagement of the Starter. Fault Code 17 indicates that an electrical failure in the Start-Enable Relay circuit was detected. The fault will not set on vehicles that use J1939 messaging to enable engine cranking.

Detection:
This fault can only be detected on transmission systems that are configured for Start Enable Relay. When the ignition key is on, the engine is not running, and the Start Enable Relay coil is not latched, this fault can be detected.

Conditions to Set Fault Code Active:
FMI 4 – Voltage Below Normal or Shorted Low: TECU detects a short to ground for at least 1 second.

Fallback:
FMI 3, 4:
• “F” flashes in gear display.
• Service light flashes (if equipped).
• Engine will not crank.

Conditions to Set Fault Code Inactive:
FMI 3, 4: An electrical short or open circuit is not detected for 2 seconds.