CAT Engine 179710 Fault Code: Fuel Rail Pressure Sensor : Abnormal Rate of Change
Fuel Rail Pressure Sensor : Abnormal Rate of Change · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Code 179710 (SPN 1797 / FMI 10) means the CAT ECM has detected that the fuel rail pressure sensor signal is staying abnormally steady instead of fluctuating with normal engine operation, usually because the sensor's 5-volt supply is missing or faulty. On C175 engines the code activates only while the engine is running, and it also has related checks during engine cranking. This is treated seriously because it can point to a wiring or ECM supply problem that may affect other pressure sensors on the same circuit.
High severity. Fuel rail pressure feedback is used by the ECM to manage fuel delivery. A stuck or invalid signal from this sensor can cause the ECM to fall back to a default value, which affects engine performance and can mask real pressure conditions. It should be diagnosed promptly rather than ignored, especially since the same supply circuit feeds many other critical sensors.
What does CAT Engine error code 179710 mean?
This code fires when the ECM's 5-volt supply to the fuel rail pressure sensor is not behaving normally. Normally, system pressure fluctuates slightly during engine operation, so the sensor signal should move around a bit. If instead the signal parks at a steady midrange value and stays there, the ECM concludes the 5-volt supply is not really reaching the sensor correctly.
On C175 engines, this specific code requires the engine to be running to become active. If the signal remains abnormally steady for more than 30 seconds, the ECM logs the code, takes a snapshot of engine data, and substitutes a default value for the fuel rail pressure sensor instead of the real reading.
There are also related crank-cycle checks tied to this same sensor: during engine cranking, the ECM checks whether it detects a deviation in the fuel rail pressure signal at all. If it does not see the expected signal behavior during crank, that is flagged as well, even before the engine reaches running speed.
What triggers a CAT Engine 179710 code?
The ECM sets this code when the fuel rail pressure sensor signal stays at a steady midrange value (rather than fluctuating as expected) for more than 30 seconds while the engine is running. Separately, during engine cranking, the ECM also checks whether it detects a deviation in the fuel rail pressure signal.
Common causes of 179710
- Damaged connectors and/or wiring in the sensor supply or signal circuit
- Electrical problem with the digital sensor supply
- Problem with the analog supply sensor or its wiring
- At least one voltage measurement at the sensor supply not reading 5.0 ± 0.2 VDC
- Problem with the ECM itself
How to troubleshoot CAT Engine 179710: first checks
- Inspect the fuel rail pressure sensor connector and wiring harness for corrosion, damage, pushed-back pins, or loose terminals
- Verify the sensor supply voltage at terminal 1 of the sensor connector reads 5.0 ± 0.2 VDC
- Check terminal 2 (sensor return) wiring for continuity and damage back to the ECM
- Check whether diagnostic code 41-3 or diagnostic code 2131-3 is also logged, since either of these can indicate that all sensors on the shared 5-volt supply circuit may have been damaged by an overvoltage event
- If a short to +Battery is suspected, inspect and repair the supply circuit before reconnecting sensors, and consider replacing any sensor that may have been exposed to overvoltage since these sensors are not protected against it
- Follow the Sensor Supply Test procedure referenced for troubleshooting this sensor circuit
How the code clears
No separate clearing step is listed beyond repairing the underlying wiring, supply, or ECM problem. Once the fuel rail pressure sensor signal returns to normal fluctuating behavior and the 5-volt supply reads correctly, the code should not reset. No reset procedure beyond fixing the fault is listed for this code.
Affected models and serial ranges
179710 appears in our records across 1 CAT Engine models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C175 | Serial range not listed in source records |
Frequently asked questions
What does CAT fault code 179710 mean?
It means the ECM detected that the fuel rail pressure sensor signal was staying abnormally steady, at a fixed midrange value, for more than 30 seconds while the engine was running, instead of fluctuating with normal pressure changes. This points to a problem with the sensor's 5-volt supply or wiring.
Is code 179710 the same as SPN 1797 FMI 10?
Yes. SPN 1797 identifies the fuel rail pressure sensor and FMI 10 means abnormal rate of change, which together form fault code 179710 on CAT C175 engines.
Can I keep running the engine with this code active?
The ECM substitutes a default value for the fuel rail pressure sensor when this code is active, which affects the accuracy of fuel system feedback. It is best to diagnose and repair the issue rather than continue running on a default value for an extended period.
What should I check first if I get this code?
Start with the connectors and wiring for the fuel rail pressure sensor, then verify the 5-volt supply voltage at the sensor connector reads 5.0 ± 0.2 VDC. Also check whether codes 41-3 or 2131-3 are logged, since those can indicate broader sensor supply damage.
Could this code mean other sensors are damaged too?
Possibly. The fuel rail pressure sensor shares its 5-volt supply circuit with many other pressure sensors. If code 41-3 or 2131-3 is also present, it is possible that all sensors on that shared circuit have been damaged by an overvoltage event, and replacement of affected sensors should be considered as a precaution.
Does this code only appear when the engine is running?
For this specific fault, yes, the engine must be running for the code to become active. There are also separate related checks during engine cranking that look at whether the ECM detects a deviation in the fuel rail pressure signal.
What causes the fuel rail pressure sensor signal to go flat?
Listed causes include damaged connectors or wiring, an electrical problem with the digital sensor supply, a problem with the analog supply sensor or wiring, a supply voltage reading outside 5.0 ± 0.2 VDC, or a problem with the ECM itself.