Diagnostic Aids

• If the PCM is replaced, the PCM must re-learn a valid password and crankshaft variation.
• If the BCM is replaced, the PCM must re-learn a valid password.
• Check for published service bulletins relating to exhibited symptoms or component operation.
• If the vehicle does not start, or starts and stalls:
  • Turn OFF the ignition and wait at least 5 seconds before trying to restart.
  • If a fault or tamper has been detected, the BCM will not forward the correct password to the PCM for a period of ten minutes, even if the condition is corrected during that time period. This may cause a DTC P1631 to set in the PCM. This timer can be monitored in the Passlock™ Data parameter of the scan tool. Once the time has elapsed, the BCM will determine if the condition is still present.
• The PCM and BCM parameters can be monitored with a scan tool.
• The Passlock™ state and the auto learn timer can be viewed in the Passlock™ Data parameter of the scan tool.
• Check the following for preventing the Passlock™ sensor from communicating with the BCM:
  • Passlock sensor
  • Ignition switch assembly
  • Passlock sensor circuitry
  • Bent pins at the small Passlock™ sensor
• If this DTC sets along with a DTC B2960, then the problem was caused by malfunctioning Passlock™ components or circuitry, not the PCM.
• Inspect all related wiring and connections including the PCM and BCM connections. These may cause an intermittent malfunction.
• An intermittent may be caused by any of the following conditions:
  • A poor connection
  • Rubbed through wire insulation
  • A broken wire inside the insulation
• Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections .

If a repair is necessary, refer to Wiring Repairs or Connector Repairs .