1998 Cadillac Eldorado BaseFACTORY OEM SERVICE PROCEDURE

DTC B1973: High Power Control Fault: Testing

  1. Remove controlled power relay. See COMPONENT LOCATIONS  . Turn ignition switch to ON position. Using DVOM, check voltage between ground and controlled power relay terminal C5 (Orange wire) at trunk compartment relay center No. 3. If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Orange wire between controlled power relay, PZM and trunk compartment fuse block.
  2. Using DVOM, measure resistance between ground and controlled power relay terminal B7 (Black wire) at trunk compartment relay center No. 3. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, check for open in Black wire between controlled power relay and PZM. If circuit is okay, replace PZM. See REMOVAL & INSTALLATION.
  3. Disconnect PZM connectors. Using DVOM, measure resistance between ground and controlled power relay connector terminal B7 (Black wire) at trunk compartment relay center No. 3. If resistance is 5 ohms or less, repair short to ground in Black wire between controlled power relay and PZM. If resistance is greater than 5 ohms, replace controlled power relay.
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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.