Low Oil Pressure Shutdown Detected
The ALLMAND-1 (COMMANDER) diesel fault code means: Low Oil Pressure Shutdown Detected. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- easy
- Estimated cost
- $5-$30 DIY for oil top-off or switch replacement. Pro diagnosis and switch swap $80-$200. Oil pump replacement $300-$600 parts and labor. Internal engine repair or replacement $1,500-$4,000+.
A $30 car code reader can't do diesel. The HD7000 reads full-system codes and does parked DPF regen, idle/speed-limit, and service resets from the cab — on everything from a 6.7 Cummins/Power Stroke/Duramax pickup to Class-8 trucks (Detroit, Paccar, CAT, Volvo, Mack, International).
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Full-system 6/9/16-pin diesel scan tool for Cummins, Paccar, CAT, Detroit and more — plug-and-play, no subscription. A cheaper way to read heavy-duty codes a basic OBD2 scanner skips entirely.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Common Symptoms
- Tower shuts down suddenly during operation and will not restart
- COMMANDER panel displays fault code 1 on the screen
- Red fault or alarm LED is lit on the side panel
- Engine cranks but shuts off within seconds of starting
- Oil pressure warning light illuminates just before shutdown
- No AC output from generator head after shutdown
- Tower lights go dark without a manual STOP command
Probable Causes (Ranked by Likelihood)
- Low engine oil level after extended runtime or slow leak Very Likely
- Faulty or stuck oil pressure switch sending false low-pressure signal Likely
- Oil pressure switch wiring shorted to ground or connector corroded Likely
- Engine oil pump worn or failing, causing actual low oil pressure Possible
- Wrong viscosity oil used, especially in cold weather causing slow pressure buildup on startup Possible
- Oil filter clogged or bypass valve stuck closed, restricting flow Possible
- Internal engine damage causing oil pressure loss (spun bearing, worn galleries) Less Likely
Step-by-Step Diagnostic Procedure
Pull the dipstick and check the oil level first. This takes 30 seconds and solves the majority of code 1 shutdowns on Allmand towers. The Kubota D902, D1105, and D1305 hold roughly 2.5 to 3.5 quarts depending on model. Add oil if low, reset the fault on the COMMANDER panel, and attempt a restart.
If oil level is correct, locate the oil pressure switch on the engine block (typically a single-wire sender near the oil filter on the Kubota D-series). With the engine OFF and ignition key in the RUN position, unplug the switch connector. If the fault clears on the COMMANDER display, the switch itself is likely defective or the wire is grounded.
Inspect the oil pressure switch wire for chafing, bare spots, or corrosion at the connector. Rental equipment takes hard use, and a wire rubbing on the block or a corroded Deutsch-style connector is a common source of nuisance code 1 trips.
With a mechanical oil pressure gauge (thread it into the sender port in place of the switch), start the engine briefly and check actual pressure. Kubota D-series spec at idle is roughly 14 PSI minimum and 43 to 71 PSI at operating speed. If pressure reads good and the switch wire checks out, replace the oil pressure switch. It is an inexpensive part.
Check the oil filter. If the unit has been running extended hours since the last service, a plugged filter can restrict flow enough to drop pressure. Replace the filter and change the oil if you are near or past the service interval (typically 250 hours or annually on Allmand towers).
If oil level is correct, the switch and wiring test good, and actual pressure reads low on the mechanical gauge, stop diagnosis here and do not continue running the engine. Low actual oil pressure with a full crankcase points to a worn oil pump, clogged oil pickup screen, or internal bearing damage. This requires a qualified engine technician.
After correcting the root cause, clear the fault on the COMMANDER display by pressing the STOP button, then cycle the key or use the panel reset sequence per your specific tower's operator manual. Attempt a restart and confirm the fault does not return within the first minute of operation.
Frequently Asked Questions
What does Allmand code 1 mean?
Code 1 on the COMMANDER controller means the engine oil pressure switch tripped. The controller detected oil pressure below the safe threshold and shut the engine down automatically to prevent internal damage. The most common reason on a light tower is that the oil level dropped low after a long rental run.
Can the tower still run with code 1 active?
No. The COMMANDER controller performs a hard shutdown when code 1 trips and will not allow a restart until the fault is cleared. This is intentional. Running a diesel engine with low oil pressure causes bearing and crankshaft damage within minutes.
How much does it cost to fix code 1?
If the fix is just adding oil, your cost is a quart or two of 15W-40 diesel oil, under $15. A new oil pressure switch runs $5 to $20 at a Kubota dealer or online. If the engine has actual low pressure from a worn pump or internal damage, expect $300 to $4,000 or more depending on what is found.
Will the tower start again after I add oil and clear the fault?
Yes, in most cases. Add oil to the correct level on the dipstick, press STOP on the COMMANDER panel to clear the fault, then restart normally. If the engine starts and shuts back down within seconds with code 1 again, do not keep cranking it. You likely have a bad oil pressure switch, a wiring fault, or a real lubrication problem that needs further diagnosis.