Overview:
The Fuller Advantage transmission is equipped with Hill Start Aid (HSA) which prevents roll-back and roll-forward while launching on grades that are 1% and greater. The HSA holds for 3 seconds using vehicle foundation wheel brakes. The Transmission Electronic Control Unit (TECU) and ABS Module communicate over the J1939 Data Link and control the HSA function. Fault Code 22 sets if the TECU loses communication with the ABS or the ABS communicates that the HSA is not available.

Detection:
The TECU communicates with the ABS module over the J1939 Data Link. If communication is lost with the ABS module or the ABS module broadcasts a message indicating HSA is not available, this fault sets Active.

Conditions to Set Fault Code Active
FMI 9 – Abnormal Update Rate: TECU detects a loss of communication with the ABS Module over the J1939 Data Link for 5 seconds while other J1939 devices are still communicating with the TECU.

Fallback:
All FMIs
• Hill Start Aid is inoperative

Conditions to Set Fault Code Inactive:
All FMIs: TECU establishes communication with the ABS module and the ABS module communicates that HSA is available.

Possible Causes:
FMI 9
1) J1939 Data Link
– J1939 Data Link damage between TECU and ABS module
– Bent, spread, corroded or loose terminals
– Wiring shorted to ground, shorted to power or open