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Test A: No Communication With Rap Module

  1. Check Fuse No. 19 For Short  - Remove fuse No. 19 (15-amp) from fuse junction panel. With an ohmmeter, measure resistance between output cavity (right side) for fuse No. 19 and ground. Observe ohmmeter reading. If resistance reading starts at greater than one megohm and steadily drop to less than 3000 ohms, go to step 5). If ohmmeter does not drop as indicated, go to next step.
  2. Check Resistance  - Observe ohmmeter reading from step 1). If ohmmeter reads less than 10 ohms, go to next step. If ohmmeter does not read less than 10 ohms, go to step 5).
  3. Check GEM  - Disconnect GEM connector C233 located under left side of instrument panel. With an ohmmeter, measure resistance as in step 1). If ohmmeter reading starts at greater than one megohm (may then steadily drop to less than 3000 ohms), replace GEM. Restore and retest system. If ohmmeter does not start at greater than one megohm, go to next step.
  4. Check RAP Module  - Disconnect RAP connector located behind lower center instrument panel. Measure resistance between output cavity for fuse No. 19 and ground. If ohmmeter reading starts at greater than one megohm, replace RAP module. Restore and retest system. If ohmmeter does not start at greater than one megohm, repair short in Tan/Light Green wire circuit. Restore and retest system.
  5. Check Dedicated Ground  - Disconnect RAP module connector. Measure resistance of Black/White wire circuit between RAP module connector and ground. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open or high resistance in Black/White wire circuit. Restore and retest system.
  6. Check Ignition RUN/ACCY Input  - Disconnect RAP module connector. Turn ignition switch to RUN position (engine off). Measure voltage of Yellow/Black wire terminal at RAP module connector. If battery voltage is present, see MODULE COMMUNICATIONS NETWORK article. If battery voltage is not present, go to next step.
  7. Check Fuse No. 12 (10-A)  - Remove fuse No. 12 (10-amp) from fuse junction panel. Measure resistance between fuse terminals. If fuse is okay, repair open in Yellow/Black wire circuit. Restore and retest system. If fuse is open, repair short in Yellow/Black wire circuit. Replace fuse No. 12. Restore and retest system.
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