GM OBD Trouble Code 51

Incorrect MEM-CAL / PROM Error

The PROM and the MEM-CAL basically serve the same function. The PROM was used in earlier model years and the MEM-CAL was used in later model years.

If the ECM detects an internal fault with the PROM or the incorrect MEM-CAl is installed, code 51 will set. The PROM/MEM-CAL is a special "chip" that is installed in the ECM, based on the particular vehicle configuration.

Fault Code Description

  • 51 - PROM/Incorrect MEM-CAL


  • Engine may not start
  • Poor engine performance

Common Problems

  • Internal fault with PROM / MEM-CAL
  • PROM or MEM-CAL incorrectly installed in ECM

0 User Comments

Sign in to comment
Why RepairPal?

Asset 71
High Quality Repairs
Your auto repair done right, only the work you need with no add ons.
Asset 72
Never Overpay
Our free estimator calculates a custom price for your vehicle repair.
Asset 73
Guaranteed Repairs
Rest easy knowing you're covered by our RepairPal Nationwide Warranty.