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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 9 (COMPUTER RELEARN PROCEDURES)COMPUTER RELEARN PROCEDURES"C" & "K" BODIESPASSWORD LEARN PROCEDURE FOR ANTI-THEFT SYSTEM (6.5L DIESEL)
1999 GMC Forward Control 5.7 R, Automatic

Password Learn Procedure For Anti-Theft System (6.5L Diesel)

1999 GMC Forward Control 5.7 R, AutomaticSECTION Password Learn Procedure For Anti-Theft System (6.5L Diesel)
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 1998 Pontiac Trans Sport, 1998 Oldsmobile Silhouette, 1998 Oldsmobile Bravada, 1998 GMC Yukon, and 1998 GMC Suburban. However, it is still accessible from the selected car via links, so may be relevant.
  1. Password learn procedure must be performed if Powertrain Control Module (PCM), passlock module or passlock sensor is replaced. A password is communicated between PCM and passlock module to provide engine operation. If PCM is replaced, the PCM must learn the password from the passlock module.
    NOTE: Ensure battery is fully charged before proceeding. Performing this procedure will cause a Diagnostic Trouble Code (DTC) P1630 to be set in the VCM. It will be necessary to use scan tool to check for DTC P1630 when performing this procedure. Ensure steps are followed in correct order or procedure may need to be repeated.
  2. Attempt to start engine. Engine will start and then stall. After engine stalls, leave ignition on for 10 minutes. After engine stalls, the SECURITY indicator light will come on for 10 minutes and then go off. SECURITY indicator light is located on upper right corner of instrument panel, just above battery charge indicator. After SECURITY indicator light goes off, turn ignition off for 30 seconds.
  3. Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off. After SECURITY indicator light goes off, turn ignition off for 30 seconds.
  4. Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off or until DTC 1630 is set in PCM.
    NOTE: DTC 1630 will be set in PCM as result of this procedure. DTC P1630 may be cleared from PCM by turning ignition off for 30 seconds and then turning ignition on again.
  5. Turn ignition off for 30 seconds. Turn ignition on and wait 30 seconds. Attempt to start engine. If engine starts, password learn procedure is complete. Ensure DTC 1630 is cleared from PCM by turning ignition off for 30 seconds and then turning ignition on again. If DTC 1630 is not cleared from PCM, perform test procedures for DTC 1630 and repair as necessary. See the appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
  6. If engine does not start, ensure procedure was properly followed. If procedure was properly followed, check for any DTCs. If any DTCs exist, perform test procedures for specified DTC and repair as necessary. See the appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
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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.