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Home >> Lincoln >> 2018 >> MKZ Select, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 553 (Supplemental Restraint System) >> Diagnosis And Testing >> Airbag and Safety Belt Pretensioner Supplemental Restraint System (SRS) >> Pinpoint Test >> PINPOINT TEST N : DTCs B1408:11, B1408:12, B1408:13 AND B1408:1A >> Notes

PINPOINT TEST N : DTCs B1408:11, B1408:12, B1408:13 AND B1408:1A: Notes

WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

Diagnostic Overview 

Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to Diagnostic Methods in Service Information for information about these practices.

Refer to Supplemental Restraint System , for schematic and connector information.

Normal Operation and Fault Conditions 

The RCM continuously monitors the RH side air curtain and circuits for the following faults:

If a fault is detected, the RCM stores DTC B1408:11, B1408:12, B1408:13 or B1408:1A in memory and sends a message to the IPC to illuminate the airbag warning indicator.

The RCM analyzes the deployment loop resistance to determine if a fault exists. The value displayed in the PID is the deployment loop resistance measured by the RCM. If the value displayed is lower or higher than the desired range (refer to diagram below), the RCM can set a DTC. As the deployment loop resistance drifts farther outside the desired range, the chance for a DTC increases. Small variations in resistance can occur due to the effect of road vibrations on terminal fit. Crimps and terminals can be affected by stress and harness movement and can cause an increase in resistance due to wire strain. These variables can result in an intermittent fault. For this reason, the test requires the PID value to be within the desired range before the fault is considered repaired, regardless if the module is reporting an on-demand DTC at the time of diagnosis. Following this direction helps make sure that minor changes in resistance do not create a repeat concern. This test uses process of elimination to diagnose each part of the deployment loop circuit including:

GFD137964Courtesy of FORD MOTOR COMPANY
DTC Description Fault Trigger Condition
B1408:11 Passenger Curtain Deployment Control 1: Circuit Short to Ground A fault is indicated when the RCM senses a short to ground on either RH side air curtain circuit for more than 6 seconds.
B1408:12 Passenger Curtain Deployment Control 1: Short to Battery A fault is indicated when the RCM senses a short to battery on either RH side air curtain circuit for more than 6 seconds.
B1408:13 Passenger Curtain Deployment Control 1: Circuit Open A fault is indicated when the RCM measures greater than the desired resistance range between the RH side air curtain circuits for more than 6 seconds.
B1408:1A Passenger Curtain Deployment Control 1: Circuit Resistance Below Threshold A fault is indicated when the RCM measures less than the desired resistance range between the RH side air curtain circuits for more than 6 seconds.

Possible Sources 

Visual Inspection and Diagnostic Pre-checks