No-start with Mazda keyless

June 14, 2013

2009 Mazda6 vehicles equipped with Advanced Keyless Entry that have DTCs B100B:11, B100C:12 or U3000:49 stored in memory and the keyless module goes into fail-safe mode may be hard to start.

B100B:11….Steering lock unit ground circuit voltage less than threshold.

B100C:12….Steering lock unit power supply circuit voltage higher than threshold.

U3000:49…..Keyless control module internal malfunction.

In some cases the keyless unit misdiagnoses a signal from the steering lock unit. When this happens, the keyless control module goes into fail-safe mode and may cause a hard-to-start condition.

NOTE: If the vehicle goes into fail-safe mode, the red keyless warning light and the red push button start indicator light come on together.

The keyless control module software has been changed at mass production to eliminate this concern. The updated keyless control module is available as P/N GSYD-67-5DZG.


  1. Verify the concern.
  2. Record the customer’s pre-set radio stations.
  3. Disconnect the negative battery cable.
  4. Replace the keyless control module according to workshop manual Section 09-14 KEYLESS CONTROL MODULE REMOVAL/INSTALLATION [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM].
  5. Re-enter the customer’s pre-set radio stations.
  6. Perform “Power Window Initialization Procedure” to restore power window functions.