⚠️ Critical Operational Note
Turning the physical equipment key switch on this generator only provides logic power to the controller. Turning the key will NOT crank or start the engine. The engine cranking cycle is controlled exclusively via the push buttons on the front interface panel.
Step-by-Step Diagnostic Procedure
1
Power On the Controller & ECU
Turn the physical equipment key switch to the RUN/ON position. The DynaGen TG350 display panel will illuminate. This step sends critical wake-up power to both the controller display and the Hatz Engine Control Unit (ECU) simultaneously. Do NOT press any other buttons yet.
2
Enter the Main Menu
Once the main home display screen has completely booted, press the Menu button on the front control interface to open the options list.
3
Navigate to Fault History
Use the Up / Down Arrow buttons to scroll through the list and highlight Fault History (or Diagnostics on some alternative firmware versions). Press the Enter / ✓ button to select it.
4
Select Engine DTCs
Inside the diagnostics menu, scroll down to select Engine DTCs (Diagnostic Trouble Codes). This instructs the TG350 to request and pull live, active broadcast faults directly from the Hatz engine's module over the J1939 CANBUS link.
5
Record the Code Parameters
The screen will display any active faults broadcasted by the engine. It is vital to accurately write down or photograph the exact parameters shown. A standard active code on the display matches this format:
ENGINE FAULT ACTIVE
SPN: 94 FMI: 18
OC: 3 Fuel Deliv Press
SPN: 94 FMI: 18
OC: 3 Fuel Deliv Press
Understanding the Code Structure
J1939 diagnostics are broken down into three core parameters that must be provided to diagnostic technicians:
- SPN (Suspect Parameter Number): Identifies the exact component or subsystem experiencing a failure (e.g., fuel delivery, timing speed sensor).
- FMI (Failure Mode Identifier): Identifies the type of problem detected (e.g., voltage too low, data erratic, mechanical issue).
- OC (Occurrence Count): Tracks exactly how many times this specific fault has registered.
Common Hatz No-Start Code Matrix
| SPN / FMI Code | Likely System Status | Recommended Initial Action |
|---|---|---|
| SPN 94 / FMI 1 or 18 | Low Fuel Delivery Pressure | Check fuel tank levels, inspect the primary pre-filter for restrictions/debris, and prime the fuel lines for trapped air. |
| SPN 636 / Any FMI | Crankshaft Position Sensor Error | Engine cannot sync injection timing. Check the physical electrical plug connection on the crankshaft sensor for loose pins or damage. |
| SPN 157 / Any FMI | Rail Pressure Sensor Error | Common rail high-pressure fuel anomaly. Do not attempt starting repeatedly. Contact a certified Hatz service provider. |
| SPN 524287 / Any FMI | Proprietary Aftertreatment Lock | Emissions or DPF system critical override. Indicates the engine ECU has implemented a hard safety lockout following a failed regen. |