Komatsu Wheel Loader CA1117 Fault Code: Persistent Data Lost Error
Also called Defective engine controller, Partial Engine Controller Data Loss Error
Persistent Data Lost Error · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CA1117 covers a defective or data-losing engine controller on Komatsu WA270, WA320, WA380, WA470, and WA500 wheel loaders. It shows up in two forms: an Action Code E03 event where the engine controller partially lost its data, and separate Action Level L04 events where the controller has an internal defect and cannot store data correctly. The engine may keep running, may stall unexpectedly, or may fail to restart.
High severity. CA1117 can mean the engine stops on its own and will not restart, or that controller data needed for normal operation and emissions-related functions has been lost. It will not always strand the machine immediately, but the risk of an unexpected stall or no-start makes this a stop-soon, diagnose-now condition rather than something to run through a shift.
What does Komatsu Wheel Loader error code CA1117 mean?
CA1117 points to a problem inside or around the engine controller itself, the module that manages engine operation and stores internal operating data. Komatsu describes two related situations under this code. The first is a partial data loss event (Action Code E03), where the engine controller lost part of its stored data, usually tied to a power supply interruption or wiring problem feeding the controller. The second is an internal controller defect (Action Level L04), where the controller cannot correctly store its internal data, including data related to the KDPF system.
In the E03 form, Komatsu's system response is to turn on the centralized warning lamp and alarm buzzer. In the L04 form, Komatsu notes no specific controller action occurs. On the machine, the practical result is similar either way: the engine can continue running normally for a while, but it may stop while running and may fail to restart once stopped. In the E03 case, the machine monitor's engine controller monitoring function also stops working normally.
Because engine controller data, including KDPF-related data, may be lost when this fault sets, Komatsu specifically calls out that appropriate follow-up action must be taken once the system recovers from the error. This is not a fault to clear and ignore even if the engine seems to run fine afterward.
Common causes of CA1117
- Loose or corroded battery terminal
- Defective battery voltage
- Defective fuse No. 10 of fuse box B
- Defective engine control cutout relay (L171), from internal disconnection or short circuit
- Defective engine control cutout relay (L172), from internal disconnection or short circuit
- Disconnection or defective contact in a wiring harness connector
- Ground fault in the wiring harness, where it contacts a ground circuit
- Short circuit in the wiring harness with another wiring harness
- Defective wiring harness connector
- Defective engine controller (internal defect)
- Defective power supply circuit to the engine controller
- Improper operation of the battery disconnect switch
How to troubleshoot Komatsu Wheel Loader CA1117: first checks
- Inspect the battery terminals for looseness or corrosion and confirm solid, clean connections
- Check battery voltage and condition, since low or defective battery voltage is a listed cause
- Check fuse No. 10 in fuse box B and replace if blown or if it shows signs of intermittent contact
- Inspect the engine control cutout relays (L171 and L172) for signs of internal disconnection or shorting, and swap or bench test if suspect
- Trace the wiring harness feeding the engine controller for disconnections, poor contact at connectors, ground faults, or chafing against other harnesses
- Confirm the battery disconnect switch is being operated correctly and in the proper sequence, since improper use is a listed cause on its own
- Turn the starting switch to ON and watch for the fault to reproduce, since that is the method Komatsu lists for reproducing this failure code
- Check the engine controller's power supply circuit for solid, uninterrupted voltage before condemning the controller itself
How the code clears
No separate clearing step is listed. Komatsu's own guidance is that because engine controller internal data, including KDPF-related data, may be lost when CA1117 sets, appropriate action must be taken once the system recovers from the error rather than simply clearing the code and moving on. Address the underlying electrical cause first (battery, fuse, relay, harness, or power supply circuit), then verify normal engine start and run behavior, including restart after shutdown, before returning the machine to service.
Affected models and serial ranges
CA1117 appears in our records across 5 Komatsu Wheel Loader models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| WA270 | Serial range not listed in source records |
| WA320 | Serial range not listed in source records |
| WA380 | Serial range not listed in source records |
| WA470 | Serial range not listed in source records |
| WA500 | Serial range not listed in source records |
Frequently asked questions
What does Komatsu CA1117 mean on a wheel loader?
It means the engine controller either partially lost its stored data or has an internal defect that keeps it from storing data correctly. It affects the WA270, WA320, WA380, WA470, and WA500 wheel loaders and can cause the engine to stall or fail to restart.
Can I keep operating the loader with CA1117 active?
It is risky. Komatsu notes the engine may continue running normally for a time, but it can stop during operation and may not restart afterward. Given the chance of an unexpected stall, it should be diagnosed and addressed before continued use rather than run through a full shift.
Will a low battery cause CA1117?
Yes. Defective battery voltage and loose or corroded battery terminals are both listed causes, along with a defective power supply circuit to the controller. Checking battery condition and connections is a good first step.
Is CA1117 related to the DPF or emissions system?
Komatsu notes that the engine controller's internal data, including KDPF-related data, may be lost when this fault occurs. That means emissions-related functions tied to the controller's stored data can be affected, so follow-up checks after the fault clears are important.
What is the difference between the two versions of CA1117 Komatsu lists?
One version (Action Code E03) is a partial data loss event tied mainly to power and wiring issues, which also turns on the centralized warning lamp and alarm buzzer. The other version (Action Level L04) points to an internal controller defect or improper use of the battery disconnect switch, with no specific controller action noted.
How do you reproduce or confirm CA1117 on a Komatsu wheel loader?
Komatsu lists turning the starting switch to the ON position as the method for reproducing this failure code, which is useful for confirming a repair before returning the machine to service.
Could a relay or fuse really cause an engine data loss code?
Yes. Komatsu specifically lists a defective fuse No. 10 in fuse box B and defective engine control cutout relays L171 and L172 as possible causes, since these can interrupt or short the power feeding the engine controller.