Diagnostic Procedure

1999 GMC Forward Control 5.7 R, AutomaticSECTION Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
  1. Observe AIR BAG warning light while turning ignition on. If AIR BAG warning light flashes 7 times, go to next step. If AIR BAG warning light does not flash 7 times, inspect vehicle for damage to wiring system, visible body damage, faulty or intermittent electrical connections or addition of aftermarket devices which could affect SIR operation. If AIR BAG warning light comes on steady go to AIR BAG WARNING LIGHT COMES ON STEADY . If AIR BAG warning light does not come on, go to AIR BAG WARNING LIGHT DOES NOT COME ON .
  2. Connect scan tool to Data Link Connector (DLC), located below left side of instrument panel, to right of steering column. If scan tool powers up, go to next step. If scan tool does not power up, inspect Class 2 data link communication circuit. See WIRING DIAGRAMS .
  3. Using scan tool, attempt to communicate with SDM. If scan tool communicates with SDM, go to next step. If scan tool does not communicate with SDM, inspect Class 2 data link communication circuit.
  4. Select SIR DTC display on scan tool. If scan tool displays current or history DTC's, go to next step. If scan tool does not display DTC's, system is okay.
  5. If scan tool displays DTC B1000, go to DTC B1000: INTERNAL SDM MALFUNCTION . If other DTC's are displayed, diagnose applicable DTC's. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION  table.
DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

Trouble Code Possible Cause
B0016  Passenger deployment loop resistance low
B0017  Passenger deployment loop resistance high
B0018  Passenger deployment loop short to ground or voltage
B0022  Driver deployment loop resistance low
B0024  Driver deployment loop short to ground or voltage
B0026  Driver deployment loop resistance high
B0051  Deployment commanded
B0053  Deployment commanded with loop malfunction
B1000  Internal SDM malfunction
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.