17730-310
21
Troubleshooting Guide
OPTIMAAX
®
Lift Axle System Air Controller Module for Freightliner
SECTION 13
Troubleshooting Guide
To diagnose OPTIMAAX issues correctly, the following steps must first be performed:
1 . With vehicle disconnected from the trailer (bobtail) and ignition on, release parking brake .
Observe if lift axle raises .
2 . Once lift axle is raised, wait 1 minute . Apply parking brake . Observe if lift axle deploys .
3 . Connect Diagnostic Tool Software, and record any ECU Current Faults and Log Data .
4 . Verify fuse (15A, located in F15 in VPDM) is operational, see Figure 11-2 in System Operation
Section of this publication .
OPTIMAAX LIFT AXLE SYSTEM – ELECTRONIC COMPONENTS
TROUBLESHOOTING GUIDE
PRIMARY CONDITION
SECONDARY
CONDITION
POSSIBLE CAUSE
CORRECTION
Lift axle does not
retract while vehicle is
disconnected from the
trailer (bobtail)
Diagnostic
Tool Software
cannot connect
Fuse is blown
Replace fuse
Wiring harness is damaged
/ connected incorrectly
Verify wiring harness connection at ECU, manifold,
and firewall . Examine visually for external damage .
Replace wiring harness as necessary .
ECU is damaged
Replace ECU
Diagnostic
Tool Software
connects, no
ECU Current
Faults reported
Wiring harness is damaged
/ connected incorrectly
Verify wiring harness connection at manifold . The
individual solenoid connections may be incorrect
Air plumbing is damaged /
connected incorrectly
Verify air plumbing at manifold is correct, and that
air lines are not crushed, damaged, or leaking .
Verify PTC fittings are not leaking .
Parking brake signal from
Single Signal-detection and
Activation Module (SSAM) is
incorrect
Open wiring harness connection at ECU 30-pin
connection . Place one multimeter lead on pin
10, place other pin on chassis fastener with good
ground contact .
With parking brake off, and ignition on, the
multimeter should read an open circuit .
With parking brake on, the multimeter should read
resistance below 150 ohms .
If pin 10 resistance values are outside this range,
replace wiring harness or relay .
Mechanical components
are damaged
Refer to Troubleshooting Guide Section in
Hendrickson Literature No . 17730-309 .
Manifold is damaged
Replace manifold
Diagnostic
Tool Software
connects, ECU
Current Faults
reported
Damaged manifold or
wiring harness
Refer to Fault Codes Section below