Diagnostic Procedure

1999 GMC Forward Control 5.7 R, AutomaticSECTION Diagnostic Procedure
WARNING: This page is about a different car, the 2002 GMC Savana and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
  1. Observe AIR BAG warning light when turning ignition on. If AIR BAG warning light flashes 7 times, go to next step. If AIR BAG warning light does not flash, inspect vehicle and easily accessible air bag system components for obvious damage, addition of aftermarket accessories, faulty or intermittent electrical connections or conditions which could cause malfunction. Diagnose air bag warning light problems. See AIR BAG WARNING LIGHT STAYS ON  or AIR BAG WARNING LIGHT DOES NOT COME ON .
  2. Install scan tool to Data Link Connector (DLC), located under left side of instrument panel. If scan tool powers up, go to next step. If scan tool does not power up, inspect data link communications circuits.
  3. If scan tool communicates with SDM, go to next step. If scan tool does not communicate with SDM, inspect data link communications circuits.
  4. Using scan tool, request Diagnostic Trouble Codes (DTC's). If current or history DTC's exist, record DTC's. Go to next step. If no DTC's exist, system is okay at this time.
  5. If scan tool displays any "U" type DTC's, diagnose and repair other system DTC's before attempting SIR system repairs. 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 open
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 open
B0035  Discriminating sensor closed or short to ground
B0036  Discriminating sensor open or short to voltage
B0051  Deployment commanded
B0053  Deployment commanded with loop malfunction
B1000  SDM malfunction
B1001  Option configuration error
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.