Diagnostic Aids

If "Scan" tester cannot communicate with ABS module, check Assembly Line Data Link (ALDL) connector for open ground circuit. Check ALDL terminals for tightness and good connection. Check "Scan" tester connector pins for damage. Verify "Scan" tester operates properly by using it on another vehicle.

Fig 1: Code I Schematic - No Scan Data

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code I Flow Chart - No Scan Data

Courtesy of GENERAL MOTORS CORP.