GM OBD Trouble Code 52

Fuel cal-pak incorrect or missing

If the ECM detects an internal fault with the Fuel cal-pak or the Fuel cal-pak is missing, code 52 will set. The Fuel cal-pak is a special "chip" that is installed in the ECM, based on the particular vehicle configuration.

Fault Code Description

  • 52 - Fuel cal-pak incorrect or missing


  • Engine may not start
  • Poor engine performance

Common Problems

  • Internal fault with Fuel cal-pak
  • Fuel cal-pak incorrectly installed in ECM

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