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Info - Parallel Hybrid Truck (PHT) (RPO HP2) - DTC P1A4A, P1A4B, P1AB2, P1AAE, B140C or APO System Fault DIC Message (Software Update)

Subject:Hybrid -- DTC P1A4A, P1A4B, P1AB2, P1AAE, B140C or APO System Fault DIC Message (Software Update)

Models:2004-2005 Chevrolet Silverado
2004-2005 GMC Sierra
with RPO HP2 -- Hybrid Vehicle



This bulletin is being revised to expand the DTCs involved and provide updated calibration information. Please discard Corporate Bulletin Number 04-06-03-013 (Section 06 -- Engine/Propulsion System).


Changes have been made to the ESCM and SGCM software that will reduce the 42V correlation faults being set. If the vehicle has set either DTC P1A4A, P1A4B P1AB2, P1AAE, B140C or an APO System Fault DIC Message, use the following procedure to verify the ESCM and SGCM calibration information.

  1. BEFORE REPLACING ANY MODULES , use the following steps to verify that the ESCM and SGCM contain the latest software calibration.
  2. Verification of ESCM and SGCM Calibrations

    1.1. F0: Diagnostics
    1.2. Select Model Year
    1.3. Select Vehicle Type
    1.4. Select Product Make
    1.5. Select Product Line
    1.6. F0: Powertrain
    1.7. Select Engine Type
    1.8. Confirm Transmission
    1.9. Select Transfer Case
    1.10. F4: I/M System Information
    1.11. F1: Vehicle Information
    1.12. A list of calibrations will appear on the screen of the Tech 2. Be sure to verify the entire list of calibrations to determine if the ESCM and SGCM have the latest calibrations based on the table listed in the Calibration Section of this bulletin. Usually, the ESCM and SGCM calibrations will be the last two listed on the second page.

    Important: Both the ESCM and SGCM must have up to date calibrations.

  3. If the ESCM and/or SGCM do not have the latest software, use the Tech 2® SPS function to update the module(s) and clear all DTCs. The latest software is available on TIS version 4.5, broadcast to dealers in April, 2005.
  4. If BOTH the ESCM and SGCM were equipped with the latest calibrations at the time the vehicle came in for service, replace the appropriate module according to the DTC that was set:
  5. • P1A4A = ESCM Hybrid Battery Current Sensor Circuit
    • P1A4B = ESCM Hybrid Battery Current Sensor Performance
    • P1AB2 = SGCM Current Correlation Fault
    • P1AAE = SGCM Phase Correlation Fault
    • B140C = SGCM APO System Fault

Calibration Information

Module -- 2004 Model Year

Calibration Part Number

ESCM

15236989

SGCM

12601135

Module -- 2005 Model Year

Calibration Part Number

ESCM

15236989

SGCM

12599030

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

J7704

Module Reprogram - Hybrid Vehicle

0.4 hr

Add:

To reprogram an additional module

0.3 hr

N5863

Module, Starter/Generator Control - Replace

2.5 hrs

N5865

Module - Gen Bat Cont (ESCM) - Replace

0.5 hr