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1997 - 2003 Corvette: Service Bulletin: Info - PCM Reprogramming and Data Line Diagnosis using J 44236-A

Subject: Info - PCM Reprogramming and Data Line Diagnosis using J 44236-A
Source: Chevrolet Dealer Technical Service Bulletin
Number:   #02-06-04-022 - (05/09/2002)

Models: 1997 - 2003 Chevrolet Corvette

All 1997-2003 Chevrolet Corvette models are equipped with two Class II data line splice packs (also called star connectors). Essential tool J 42236-A is designed to connect to these splice packs and is required for PCM reprogramming and data line diagnosis.

The J 42236-A allows the technician to isolate one module at a time from all others on the Class II data line. When a module is isolated, the Tech 2 can be used to read data, send commands and reprogram that module (if applicable).

When reprogramming the PCM, the on-board control modules may attempt to communicate with the PCM across the Class II data link. When this happens, the reprogramming procedure is interrupted and will result in a non-functional PCM and require replacement of the PCM. When reprogramming the PCM, the service method listed in Service Information (SI) must be used to ensure that no other modules in the vehicle attempt to communicate with the PCM during the reprogramming procedure.



Before installing the J 42236-A for diagnosis or reprogramming, check and record all stored DTCs.

  • J 42236-A installs to the splice pack/star connectors. These splice packs are located to the left of the body control module (BCM). The splice packs/star connectors are stand alone and do not plug into the BCM. The BCM is located behind the passenger floor access panel.
  • Both splice pack/star connector shorting bars need to be removed from the splice pack/star connector. This can be done by squeezing both ends of the shorting bar and pulling it away from the splice pack.
  • The splice packs/star connectors may have to be removed from their mounting pins in order to install the J 42236-A. The splice packs/star connectors must be visually inspected to ensure the proper cable from the J 42236-A is installed on the correct splice pack/star connector.
  • Cable #1 connects to the star connector with eight, nine or ten wires. Cable #2 connects to the star connector with four incoming wires.

Refer to the Information Card included with the tool (and shown in the illustration) for the correct J 42236-A settings in order to access the desired Class II module.

After Data Line Diagnosis or PCM Reprogramming

  1. Disconnect the J 42236-A and reinstall both shorting bars on to the splice packs. Both splice pack/star connector shorting bars are identical and must be installed for proper vehicle operation.
  2. Check and clear all vehicle modules for trouble codes. Refer to SI in order to correct any trouble codes that may have been recorded prior to diagnosis or reprogramming and are still present.
  3. Any trouble codes that may appear after diagnosis or reprogramming must also be diagnosed using SI.

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GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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