Table 3-3. Operator Troubleshooting
TEST OR INSPECTION
APU FAILS TO CRANK
Step 1. Check for battery switch in cab set to OFF.
Set battery switch to BOTH.
Step 2. Check for batteries low on charge.
APU CRANKS BUT WILL NOT START
Step 1. Check for empty fuel tank.
Step 2. Check for intake air too cold to enable initial combustion.
Use manifold preheater (see para 2-16 .).
APU RUNNING UNEVEN AND STALLS FREQUENTLY
Step 1. Check for almost empty fuel tank.
Step 2. Check for truck batteries low on charge making alternator hard to drive.
Start main engine to charge truck batteries.
If main engine won't start, refer to Unit Maintenance.