Diagnostic Procedures

2004 Oldsmobile Bravada AWDSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
  1. Install scan tool. Does the scan tool power-up? If yes, go to next step. If no, perform SCAN TOOL DOES NOT POWER UP IN DATA LINK COMMUNICATIONS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  2. Turn ignition on, with engine off. Attempt to establish communication with the listed control modules. If you are using a Tech 2, obtain the information using the Class 2 Message Monitor feature: The Body Control Module (BCM), Electronic Brake Control Module (EBCM), Instrument Panel Cluster (IPC), PCM, Sensing And Diagnostic Module (SDM) and the Vehicle Theft Deterrent (VTD). Does scan tool communicate with all control modules? If yes, go to next step. If no, perform SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  3. Attempt to start engine. Does engine start and idle? If yes, go to next step. If no, go to NO-START DIAGNOSIS in BASIC DIAGNOSTICS PROCEDURES - 2.2L SONOMA & S10 PICKUP article.
  4. Select the DTC display function for the BCM, EBCM, IPC, PCM, SDM and VTD. Does scan tool display any DTCs? If yes, go to next step. If no, go to step  9 .
  5. Using scan tool, save or capture the Powertrain DTC Information, Store Information. When complete, go to next step.
  6. Does scan tool display DTCs which begin with a "U"? If yes, perform SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no, go to next step.
  7. Were any of the PCM DTCs P0601, P0602 or P1621 set? If yes, go to DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 OR P2610: PCM MEMORY  . If no, go to next step.
  8. Does scan tool display DTC P0562, P0563, P0621, P0622, P1637, or P1638? If yes, diagnose affected DTC(s). Go to DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, go to next step.
  9. Is customer's concern related to the automatic transmission? If yes, diagnose transmission. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If no, go to next step.
  10. Is customer's concern with Inspection/Maintenance (I/M) testing? If yes, go to INSPECTION/MAINTENANCE SYSTEM CHECK  under DRIVE CYCLES. If no, go to next step.
  11. Check for the following symptoms: Hard start, surges/chuggles, lack of power, sluggishness/sponginess, detonation/spark knock, hesitation, sag, stumble, cuts out, misses, poor fuel economy, poor fuel fill quality, rough idle, unstable idle, incorrect idle, stalling, dieseling, run-on, backfire, Malfunction Indicator Light (MIL) inoperative, or MIL always on. Did you find and correct the condition? If yes, system is okay. If no, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L SONOMA & S10 PICKUP article.
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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.