K Yukon/Denali 4WD V8-5.7L VIN R (2000)
Technical Service Bulletin # 01-08-56-002A
Date: 010601
Security System - Lamp ON/DTC B2960 Set
File In Section: 08 - Body and Accessories
Bulletin No.: 01-08-56-002A
Date: June, 2001
TECHNICAL
Subject:
Security Lamp Illuminated on the IP, Engine Stalls, No Start, DTC B2960 (Security System Sensor Data Incorrect but Valid) Set (Inspect and Repair
Cause of DTC B2960)
Models:
1999-2001 Chevrolet and GMC C/K Pickup and Utility Models (Silverado, Sierra, Tahoe, Suburban, Yukon, Yukon XL)
This bulletin is being revised to add information on inspecting for electrical intermittent conditions and important connector C201 tightening steps.
Please discard Corporate Bulletin Number 01-08-56-002 (Section 08 - Body and Accessories).
Condition
Some customers may comment on the following conditions. These symptoms may be intermittent.
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Security lamp illuminates while driving. The Security lamp may be On or Off when the customer brings the vehicle to the service facility.
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The engine cranks but will not start and the Security lamp is flashing.
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The engine starts then stalls and the Security lamp is flashing.
Cause
Condition(s) may be due to an incorrect Passlock(TM) sensor voltage received by the body control module (BCM) from the Passlock(TM) sensor due to
the following conditions. Most intermittent conditions are caused by faulty electrical connections or wiring.
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A 7 ohm variation in the sensor ground circuit wiring, circuit 1057
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A 100 ohm variation in the Passlock(TM) sensor signal wiring circuit, circuit 1836.
Inspect for the following items:
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Broken wiring inside the insulation.
^ A poor connection between the male and female terminal at the connector. Refer to Testing for Proper Terminal Contact under Testing for
Intermittent and Poor Connections in Wiring Systems for the specific procedure.
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A poor terminal to wire connection. Some conditions that fall under this description include poor crimps, poor solder joints, crimping over the
wire insulation instead of the wire itself, and corrosion in the wire to terminal contact area.
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Wire insulation that is rubbed through. This causes an intermittent short as the bare area touches other wiring or parts of the vehicle.
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A poor connection between the male and female terminal at a connector. This poor connection may be the result of contamination or deformation.
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Contamination may be caused by the connector halves being improperly connected. A missing or damaged connector seal, damage to the
connector itself, or exposing the terminals to moisture and dirt can also cause contamination. Contamination, usually in the underhood or
underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit.
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Separate the connector halves.
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Visually inspect the connector halves for contamination. Contamination may result in a white or green build-up within the connector body
or between terminals. This causes high terminal resistance, intermittent contact, or an open circuit. An underhood or underbody connector
that shows signs of contamination should be replaced in its entirety including the terminals, the seals, and the connector body.
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Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves,
or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal connector tang, can result in poor
