Intermittent Low Battery Voltage, Engine Will Not Crank, Cranks But No Start, Charging System Light On, Service Battery Charging System Message Displayed, DTC B1405 and/or B1516 Set (Reprogram BCM)

This bulletin is being revised to provide updated service information and a new labor operation code. Please discard Corporate Bulletin Number 06-06-03-013 (Section 06 -- Engine/Propulsion System).

Some customers may comment of one or more of the following conditions:

This condition may be caused by Body Control Module (BCM) calibrations that create a lower battery state of charge than intended in low electrical power usage modes.

A revised calibration has been developed to address these conditions. Technicians are to reprogram the BCM using SPS with the latest software available on TIS2WEB. Refer to the Body Control Module Programming and Setup procedure in SI (Document ID# 1741198). As always make sure your Tech 2® is updated with the latest software version.

Usually if a vehicle will start and then not start in a very short period of time, the condition may be created by a loose or corroded connection. In most situations a battery in a good state of health cannot be drained within minutes without a major and most likely very obvious short. The following items are also possible areas of starting and charging system concerns and should be considered as a part of your diagnosis. For more information refer to the Symptoms -- Engine Electrical diagnostic procedure in SI (Document ID# 1703276).

1. Verify the battery cable connections. It is possible for the negative or positive terminal connector nut to tighten without making a good electrical connection on the battery terminal. The top of the negative battery post should be slightly above the top of the cable clamp.
2. Verify the battery condition and state of charge using the Midtronics tester and a VAT40 or equivalent tester. Refer to the following diagnostic procedures in SI for additional information.

•	Battery Common Causes of Malfunction (Document ID# 1703244)

•	Battery Inspection/Test (Document (ID# 1703241)

•	Battery Charging (Document ID# 1703243)

3. Verify proper operation of the charging system. Refer to the Charging System Test procedure in SI (Document ID# 1703783).
4. Verify that the vehicle does not have a parasitic battery drain. Refer to the Battery Electrical Drain/Parasitic Load Test procedure in SI (Document ID# 1741191).
5. Verify that the front and/or rear Heating, Ventilation and Air Conditioning (HVAC) blower motor turns off with the key in the OFF position. If the blower motor stays on, refer to the Blower Motor Always On diagnostic procedure in SI (Document ID# 1701247).
6. Ask the customer if they use the accessories (Radio, DVD player, etc.) with the key in the ON position but with the engine off. This may contribute to a low battery state of charge and difficulty cranking the engine. If the customer uses their accessories with the engine off ask them to turn the key to the ACC position instead of the ON position.
7. If the vehicle is equipped with aftermarket accessories, verify that they are not a source of concern. Remove or disable if necessary and retest the vehicle. Refer to the Checking Aftermarket Accessories procedure in SI (Document ID# 816776).
8. Verify that there are no loose connections at the 175 amp mega fuse.
9. Verify that the Retained Accessory Power (RAP) system is operating properly. The radio and accessories should shut off once the key is removed from the ignition and the driver's door is opened. For more information refer to the Retained Accessory Power (RAP) Malfunction procedure in SI (Document ID# 1776533).
10. Refer to the following Bulletins and PIs for additional areas of concern.

•	A fuel pump relay sticking concern. Refer to Corporate Bulletin number 06-06-03-011B.

•	An ignition switch concern and a loss of GM LAN data due to an unwanted ground. Refer to Corporate Bulletin 06-08-45-010.

•	A rear door lock relay sticking concern. Refer to Preliminary Information bulletin PIT3984 (Document ID# 1820437).

For vehicles repaired under warranty, use: