B108B FORD - Start Button Circuit 'A'

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
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Possible causes

  • Faulty Start Button Switch
  • Start Button Switch harness is open or shorted
  • Start Button Switch circuit poor electrical connection
  • Faulty Body Control Module (BCM)

Tech notes

B108B:23 Start Button Circuit 'A' Signal Stuck Low
B108B:24 Start Button Circuit 'A' Signal Stuck High
B108B:2F Start Button Circuit 'A' Signal Erratic

Possible symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

B108b Ford Description

Conventional Ignition Switch:

The ignition switch is a multiple position rotary switch that is controlled by a lock cylinder and a key. The ignition switch provides voltage to the ACC, ON, or START-designated circuits depending on the position it is placed. The Body Control Module (BCM) calculates the positions based on the voltage received from the ACC and ON-designated circuits.

The key removal inhibit solenoid (also known as the key release interlock actuator) is an electronically controlled solenoid that prevents the ignition lock cylinder from being turned to the OFF position unless the gear selector lever is in the PARK position. The key removal inhibit solenoid is part of the ignition switch.

Push Button Ignition Switch:

The push button ignition switch is used instead of a conventional ignition switch to achieve the various ignition modes. The push button ignition switch is a momentary dual contact switch. Both sets of contacts are normally open and receive the voltage at all times. When the START/STOP button is pressed, the voltage is sent to the BCM, the RFA module, and the PCM to indicate a button press.

The ignition switch has a LED for switch illumination when the backlighting is activated.

OBDII Code B108b Ford - Start Button Circuit 'A' - AutoCodes.com

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B108B FORD Comments

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