CAT Engine 16276 Fault Code: Fuel Pump Relay:Current Above Normal
Also called Fuel Pump Relay : Current Above Normal, Fuel Pump Relay Current Above Normal, Fuel Pump Relay Short to Ground, Fuel Pump Relay current above normal, Fuel Pump Relay short to ground
Fuel Pump Relay:Current Above Normal · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT code 16276 (SPN 1627 / FMI 6) means the ECM has detected a short to ground or an above-normal current condition at the fuel pump relay output while the driver output is on and battery voltage is above 9 VDC. On these engines, this shuts down the electric fuel priming pump, and injectors will keep firing until the engine runs out of fuel and stalls.
High severity. The fuel pump will not operate once this code sets, and the engine will keep running on remaining fuel pressure until it stalls from fuel starvation. This is not an immediate safety hazard by itself, but it will strand the machine and can happen without warning once fuel pressure drops.
What does CAT Engine error code 16276 mean?
CAT code 16276 covers the fuel pump relay circuit on C175, C27, and C32 engines. The ECM controls this relay to power the electric fuel priming pump (EFLP), which supplies positive fuel pressure to the low pressure side of the fuel system and to the high-pressure fuel pump.
This code triggers when the ECM has the driver output on, but detects either an open circuit or a short to ground at the relay output for the fuel pump, while battery voltage is greater than 9 VDC. Related descriptions of this same code also cover a short to battery voltage or an open circuit lasting 60 seconds, and a high current condition in the EFLP relay circuit lasting more than 2 seconds.
Once the code is active, the fuel pump relay output is disabled and the electric fuel priming pump will not run. The injectors keep firing on whatever fuel pressure remains in the system, so the engine will continue running until it stalls from lack of fuel. The code is logged, and the warning light comes on.
What triggers a CAT Engine 16276 code?
The ECM sets this code when all of the following are true: the driver output for the fuel pump relay is on, an open circuit or short to ground is detected at the relay output for the fuel pump, and battery voltage is greater than 9 VDC. Related versions of this fault also describe an open circuit or short to battery voltage lasting 60 seconds, or a high current condition in the EFLP relay circuit for more than 2 seconds (this can only be detected when the output driver is not activated). If current returns to normal for 6 seconds, the diagnostic code will be cleared automatically.
Common causes of 16276
- Damaged or corroded connectors and wiring in the fuel pump relay circuit, including the harness between the ECM and the relay connector
- A faulty fuel pump relay that needs to be replaced
- A short between the connector for the fuel pump relay and the ECM
- A problem with the wiring between the ECM and the fuel pump relay connector, including wire A893-OR between the relay connector and the electric fuel priming pump
- Loss of continuity on wire 229-BK to engine ground
- A blown fuse or a tripped 20 Amp circuit breaker for the engine ECM
- A faulty electric fuel priming pump (EFLP) that needs to be replaced
- An intermittent electrical problem in the harness
- Incorrect supply voltage to the relay circuit
- A faulty ECM that needs to be replaced
How to troubleshoot CAT Engine 16276: first checks
- Inspect all connectors and wiring for the fuel pump relay and the electric fuel priming pump for damage, corrosion, or loose pins
- Verify that battery voltage is present on terminal 1 at the connector for the fuel pump relay. If voltage is present there but the pump still will not run, replace the fuel pump relay
- Check that the 20 Amp circuit breaker for the engine ECM is not tripped, and check for blown fuses in the circuit
- Verify that wire 229-BK has continuity to engine ground
- Inspect and repair wire A893-OR between the fuel pump relay connector and the electric fuel priming pump as needed
- Use the diagnostic scan tool's Override Parameters test (Diagnostics > Diagnostic Tests > Override Parameters) to energize the fuel pump relay directly with the engine at 0 rpm, and confirm the ECM can hold the output on for 120 seconds without the fault reappearing
How the code clears
The ECM will keep attempting to activate the fuel pump relay after the fault is detected. If the current in the circuit is normal for 6 seconds, the diagnostic code will clear on its own. No separate reset procedure beyond repairing the wiring, connector, relay, or ECM fault is listed for this code.
Affected models and serial ranges
16276 appears in our records across 3 CAT Engine models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C175 | Serial range not listed in source records |
| C27 | Serial range not listed in source records |
| C32 | Serial range not listed in source records |
Frequently asked questions
What does CAT code 16276 mean?
It means the ECM has found either a short to ground or an above-normal current condition in the fuel pump relay circuit while trying to power the relay, with battery voltage above 9 VDC. This disables the electric fuel priming pump.
Will the engine keep running with code 16276 active?
Yes, initially. The injectors keep firing on remaining fuel pressure, so the engine keeps running until it eventually stalls from fuel starvation once low pressure fuel supply is lost.
What is the electric fuel priming pump (EFLP) for?
It supplies positive fuel pressure to the high-pressure fuel pump. The ECM energizes it through the fuel pump relay when the key is turned on, and it runs continuously whenever the engine is cranking or running.
Which wires and terminals are most commonly involved in this fault?
Wire 229-BK should be checked for continuity to engine ground, and wire A893-OR between the fuel pump relay connector and the electric fuel priming pump should be inspected and repaired if damaged. Terminal 1 at the relay connector should show battery voltage when the circuit is healthy.
Does this code clear itself?
It can. If the ECM sees normal current in the circuit for 6 seconds after detecting the fault, the diagnostic code will clear automatically. If the underlying wiring, relay, pump, or ECM problem is not fixed, it will likely return.
How do I test the fuel pump relay with a scan tool?
Use the Override Parameters test under Diagnostics > Diagnostic Tests on the scan tool. This lets you energize the fuel pump relay directly. The test only works with engine speed at 0 rpm, and the ECM will hold the relay output on for 120 seconds.
Which engines use this fault code?
This code applies to C175, C27, and C32 CAT engines that use an electric fuel priming pump and relay in the low pressure fuel system.