Engine-Codes - Generic - B1440

B1440 Code - Power Mode Master Input Circuits Mismatch

- Code Popularity: 36,107 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC B1440?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Ignition Switch
  • Ignition Switch harness is open or shorted
  • Ignition Switch circuit poor electrical connection
  • Faulty Body Control Module (BCM)
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How to Fix the DTC B1440?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the B1440 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

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

What Does the B1440 Code Mean?

The vehicle Power Mode Master (PMM) is the Body Control Module (BCM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination of the power mode. The PMM receives the ignition switch signals, and additionally a reference voltage signal from the BCM, through the ignition switch, and back to the BCM. There are redundancies within the PMM system that can allow operation of certain subsystems when there are faults in the ignition switch circuits. Other information such as serial data input from other modules and DTCs is also used to determine what power mode signals and information is transmitted by the PMM. The BCM logic uses all this information to identify the operator's desired power mode and activate specific discrete signals, and serial data messages for the operation of different subsystems as necessary. Other modules which have switched voltage inputs may operate in a default mode if the PMM serial data message does not match what the individual module can detect from its own connections.
The PMM will activate relays and other direct outputs of the PMM as needed according to the calculated power mode. Some relays controlled by the BCM are switched ignition voltage outputs that are pass through circuits within the BCM directly from the ignition switch. If these circuits short to ground, the B+ circuit fuse to the ignition switch will open.

B1440 Code - Power Mode Master Input Circuits Mismatch

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