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GM OBD Trouble Code 41

By Jim Taddei, May 1, 2009

Ignition Control Error

MEM-CAL Error

Computer Controlled Ignition Cam Sensor Signal Error

  • Depending on the model, code 41 can refer to three different systems.
  • Please choose from one of the above links for specific information on each system.

Ignition Control Error

The ECM monitors the ignition module performance. Code 41 can set when the ignition system performance does not meet factory specifications.

Fault Code Description

  • 41 - Ignition control error

Symptoms

  • Engine cranks but won't start
  • Engine stalling
  • Lack of power

Common Problems

  • Faulty Ignition Module
  • Faulty Crankshaft Position sensor
  • Faulty ECM or wiring issue between ECM and ignition module

MEM-CAL Error

If the ECM detects an internal fault with the MEM-CAL, code 41 will set. The MEM-CAL is a special "chip" that is installed in the ECM, based on the particular vehicle configuration.

Fault Code Description

  • 41 - MEM-CAL error

Symptoms

  • Engine may not start
  • Engine stalling or erratic performance

Common Problems

  • Internal ECM or MEM-CAL fault

Computer Controlled Ignition Cam Sensor Signal Error

The ECM receives a signal from the Camshaft Position Sensor based on the position of the camshaft. The ECM uses information from this sensor to help calculate fuel delivery and spark timing.

Fault Code Description

  • 41 - Computer Controlled Ignition Cam Sensor Signal error

Symptoms

  • Hard starting
  • Lack of power
  • Engine ping

Common Problems

  • Failed camshaft interrupter magnet on camshaft sprocket
  • Cam sensor timing out of adjustment

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