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Home >> Cadillac >> 1996 >> Fleetwood Base >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Central Control Module >> Diagnosing & Repairing CCM DTCS >> DTC 21, Rap Enable Circuit (CKT Open Or Shorted To Ground) >> Testing
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DTC 21, Rap Enable Circuit (CKT Open Or Shorted To Ground): Testing

  1. Turn ignition switch to OFF position. Remove both RAP relays. Disconnect CCM connector C1. Using DVOM, check for continuity between RAP wiper relay connector terminal C2 and ground. If continuity is present, repair short to ground in RAP relays control circuit. If continuity is not present, go to next step.
  2. Using DVOM, measure resistance between RAP power relay terminals A1 and C2. Also, measure resistance between RAP wiper relay terminals A1 and C2. Resistance should be 40-100 ohms for RAP power relay and 70-150 ohms for RAP wiper relay. If resistance measurements are not as specified, replace defective relay. If resistance measurements are as specified, go to next step.
  3. Using DVOM, check for continuity between RAP power relay terminals C1 and C2. Also, check for continuity between RAP wiper relay terminals C1 and C2. If continuity is present for any measurement, replace defective relay. If continuity is not present, go to next step.
  4. Using DVOM, measure voltage between RAP power relay connector terminal A1 and ground. Also, measure voltage between RAP wiper relay connector terminal A1 and ground. If battery voltage is not present at both relay terminals, repair short to ground in battery positive maxi-fuse No. 2 circuit for appropriate relay. If battery voltage is present, go to next step.
  5. Install both RAP relays. Turn ignition switch to RUN position. Using DVOM, measure voltage between CCM connector C1 terminal A4 and ground. If battery voltage is not present, repair open in RAP relays control circuit. If battery voltage is present, go to next step.
  6. Turn ignition switch to OFF position. Check for poor connections at CCM connector. If connections are okay, reconnect CCM connector and all other components. Clear DTCs and check if DTC resets. If DTC resets, replace CCM. If DTC does not reset, problem may be intermittent. Try to recreate fault while performing test by wiggling wiring and connectors. Check for poor connections at all connectors that may be causing intermittent condition.
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