Nissan Altima B2109 Steering Lock Relay

One such code, B2109, is associated with the steering lock relay. In this article, we’ll explore the detailed description, causes, and solutions provided by Nissan for this issue.

DTC B2109 Overview

The DTC B2109 relates to the detection logic of the steering lock relay being in the OFF position for about 1 second, as identified by the Intelligent Power Distribution Module Engine Room (IPDM E/R). This occurs even when the IPDM E/R receives steering lock relay ON/OFF signals from the Body Control Module (BCM).

Causes of DTC B2109

The potential causes of DTC B2109 include issues with the harness or connector in the power supply circuit, problems with the IPDM E/R, or issues related to the battery. It’s essential to perform thorough trouble diagnosis for associated DTCs like U1000 and U1010 before addressing B2109.

Nissan’s Fix for the Problem

Interestingly, Nissan’s fix for this problem involves a straightforward solution for newer models. Some users have reported success by turning the car on and pulling out the fuse in the engine bay, eliminating the need for an expensive repair. However, this workaround may result in a minor delay before the engine starts.

Personal Experience and DIY Fix

Recognizing the Issue

For Nissan Altima owners experiencing the steering lock problem, a yellow key light on the dashboard and the inability to start the car are common indicators.


A user with limited mechanical expertise shared a quick DIY fix that only requires basic tools, such as needle-nose pliers, a mallet, and screwdrivers. By accessing the panel under the steering wheel and locating the metallic box representing the steering lock mechanism, users can address the issue in about 15 minutes.

Steps for DIY Fix

  1. Remove the panel under the steering wheel by opening the driver’s side door and extracting the piece from the door jam.
  2. Unclip the panel under the steering wheel, and remove the screw near the interior fuse box.
  3. Gain access to the steering lock mechanism at the base of the steering column, a metallic box about the size of a fist.

Nissan Altima 2007-2012 Service Manual Insights

Steering Lock Relay Operation

The steering lock relay ON signal is transmitted to the IPDM E/R by the BCM via CAN communication. The IPDM E/R, in turn, activates the steering lock relay and communicates the release of the steering to the BCM.

DTC Logic Confirmation Procedure

The service manual provides a detailed diagnostic procedure for confirming DTC B2109. It involves pressing the push-button ignition switch under specific conditions and checking the self-diagnostic result with CONSULT-III.

Diagnosis Procedure

  1. Check Power Supply Circuit: Verify the normal operation of the IPDM E/R power supply circuit.
    • Result: If normal, proceed to the next step; if not, repair the malfunctioning parts.
  2. Check Fuse: Examine the 10A fuse (No. 40) located in the IPDM E/R after turning off the ignition switch.
    • Result: If the inspection result is normal, replace the IPDM E/R; otherwise, investigate the harness for open or short between IPDM E/R and the battery, and check the fuse.

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