What causes a SPN 4202 code?

SPN 4202 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 4202 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4202 active.

How do I fix SPN 4202?

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 4202

Allison transmission code P4202

What it means

C3 Clutch Solenoid Circuit Low. The Transmission Control Module (TCM) has detected an unexpected low voltage or ground condition on the control circuit for the C3 clutch solenoid.