For 1990-2009 cars

# No Serial Data Communications Using The Tech 1 - keywords body CCM commcommunication crank display DTC EBTCM ECM electrical failure fuse ground HVAC ignition information inoperative module no on

Subject: | No Serial Data Communications Using the Tech 1

Models: | 1986-1996 Pontiac Firebird w/5.0 or 5.7 litre engine

| 1986-1996 Chevrolet Camaro w/5.0 or 5.7 litre engine

| 1986-1996 Chevrolet Corvette

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

### Condition/Concern:

There have been numerous questions regarding serial data communications with certain vehicles. These vehicles require adapters between the Tech 1 and the Assembly Line Data Link (ALDL).

For all 1986 model year and newer Camaros, Firebirds and Corvettes with either the 5.0 or 5.7 litre engines it is mandatory that adapters between the Tech 1 and the ALDL be used to communicate with certain modules.

The part numbers for the adapter are P/N 3000091. The title on the cable is listed as "Tech 1 OBDII Vehicle Interface Module (VIM)", and TA02149 and is called a GM PIN E adapter.

Concerns which encompass no communication with the ECM or the CCM will be corrected with the use of these adapters.

### Recommendation/Instructions:

Use this adapter between the Tech 1 and the vehicle ALDL to communicate with the serial data line.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.