What causes a SPN 1078 code?

SPN 1078 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a SPN 1078 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 1078 active.

How do I fix SPN 1078?

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

J1939 SPN

SPN 1078

Engine Fuel Injection Pump Speed Sensor Signal Mis-Match

What it means

Indicates a loss of synchronization or an invalid signal from the fuel injection pump speed sensor in relation to the engine crankshaft position sensor.