P1093 — HP Fuel Rail Pressure Low During Power Enrichment
What it means: HP Fuel Rail Pressure Low During Power Enrichment.
How serious / can you keep driving: Critical. Stop as soon as it's safe.
Check first: Test lift pump volume and pressure
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Ocala, FL
Closest first. Tell them P1093 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Ocala, FL · (352) 830-1899
- 0.0 mi away — based in Ocala, FL · (352) 620-0740
- 0.0 mi away — based in Ocala, FL · (352) 497-0277
Seen on: Heavy Truck/Diesel
What P1093 means
HP Fuel Rail Pressure Low During Power Enrichment. Common causes: CP3/CP4 pump worn.
How serious is it?
Critical. Stop as soon as it's safe.
Most likely causes
- CP3/CP4 pump worn
- Fuel filter restriction
- lift pump weak
First moves (roadside)
- Test lift pump volume and pressure
- replace HP pump if injection quantity test fails
FAQ
HP Fuel Rail Pressure Low During Power Enrichment. Common causes: CP3/CP4 pump worn.
Critical — Stop as soon as it's safe.
The most common cause is: CP3/CP4 pump worn. Other possibilities include Fuel filter restriction; lift pump weak.
Stop as soon as it's safe. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P1093, or share the same subsystem.
- Injector Metering Rail 1 Pressure - Data Valid But Below Normal Operating Range (XPI common rail fuel pressure too low) (SPN 157 FMI 1)
- Fuel Delivery Pressure — Low (SPN 94 FMI 1)
- Injection Rail Pressure — Below Normal (SPN 157 FMI 18)
- Injector Metering Rail 1 Pressure - Data Valid But Above Normal Operating Range (XPI common rail fuel pressure too high) (SPN 157 FMI 0)
- Injector #1 open circuit (SPN 651 FMI 5)
- Injector #2 open circuit (SPN 652 FMI 5)
- Injector #3 open circuit (SPN 653 FMI 5)
- Injector #4 open circuit (SPN 654 FMI 5)
Same symptom: Fuel delivery
Other codes on the tank-to-injector path — pressure, filters, water and the pump.
- Fuel System Leak Detected - Large Leak (P0093) · Fuel System
- High-Pressure Fuel System Relief Valve Open (P2BAD) · Fuel System
- Injector #5 open circuit (SPN 655 FMI 5) · Fuel System
- Injector #6 open circuit (SPN 656 FMI 5) · Fuel System
- Fuel Rail/System Pressure Too Low (P0087) · Fuel System
- Fuel Rail/System Pressure Too High (P0088) · Fuel System
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.