P1093 on GMC
Fuel Rail Pressure Low During Power Enrichment / Fuel Rail Pressure Too Low (manufacturer-specific)
P1093 on GMC vehicles indicates fuel rail pressure low during power enrichment / fuel rail pressure too low (manufacturer-specific). Au7o has documented this code across 1 GMC model — most commonly on Sierra 2500HD. P1093 is a manufacturer-specific powertrain code indicating insufficient fuel rail pressure. On GM gasoline applications it is typically 'Fuel Rail Pressure Low During Power Enrichment,' meaning the rail could not maintain the pressure the computer commanded during hard acceleration. On many diesel and other applications it is reported as 'Fuel Rail Pressure Too Low' or a fuel rail pressure sensor circuit fault. Low rail pressure can cause hesitation, power loss, and potential lean operation, so it should be addressed promptly. Typical repair costs on GMC range from $3,500 to $6,500, depending on the specific model and root cause.
Common Causes of P1093
- •Weak or failing fuel pump (lift or high-pressure pump)
- •Clogged fuel filter or restricted fuel supply line
- •Faulty fuel pressure regulator
- •Faulty fuel rail pressure sensor or wiring
- •Leaking or returning fuel injectors
- •Low fuel volume / restricted fuel delivery under load
- •Air or leaks in the fuel system
P1093 on GMC by Model
GMC Sierra 2500HD(1 issue)
- LB7 Duramax Injector Body Cracking and Ball-Seat Erosion Causing Fuel-in-Oil Dilution2001-2004
The 2001-2004 6.6L Duramax RPO LB7 uses injectors buried under the valve covers that are notorious for failing well before 150,000 miles. GM's own analysis attributed the failures to fuel injector body cracks, ball seat erosion, and high-pressure seal extrusion. A leaking injector dumps unburned diesel into the cylinder and past the rings into the crankcase, raising the oil level and diluting it. Owner reporting on duramaxforum.com and silveradosierra.com consistently puts first failures in the 100k-150k range, and because the injectors sit under the valve covers the labor to reach them is far higher than on the later LLY/LBZ engines, where injectors are accessible from the top. This is an LB7-only failure mode - the LLY and later injectors were redesigned and do not share it.
Looking for P1093 on a different make?
View P1093 across all makes →Frequently Asked Questions
What does P1093 mean on GMC?▼
P1093 stands for "Fuel Rail Pressure Low During Power Enrichment / Fuel Rail Pressure Too Low (manufacturer-specific)." P1093 is a manufacturer-specific powertrain code indicating insufficient fuel rail pressure. On GM gasoline applications it is typically 'Fuel Rail Pressure Low During Power Enrichment,' meaning the rail could not maintain the pressure the computer commanded during hard acceleration. On many diesel and other applications it is reported as 'Fuel Rail Pressure Too Low' or a fuel rail pressure sensor circuit fault. Low rail pressure can cause hesitation, power loss, and potential lean operation, so it should be addressed promptly. On GMC specifically, this code is documented across 1 model.
What causes P1093 on GMC vehicles?▼
Common causes on GMC: Weak or failing fuel pump (lift or high-pressure pump), Clogged fuel filter or restricted fuel supply line, Faulty fuel pressure regulator, Faulty fuel rail pressure sensor or wiring, Leaking or returning fuel injectors. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P1093 on a GMC?▼
Repair costs on GMC range from $3,500 to $6,500, depending on the specific model and root cause.
Which GMC models have P1093 documented?▼
Au7o has documented P1093 on 1 GMC model: Sierra 2500HD.