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Home >> Pontiac >> 2000 >> Firebird Base, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P1260: Fuel Pump Speed Relay Control Circuit (Grand PRIX & Regal) >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
  2. Turn ignition off. Disconnect PCM and fuel pump relay harness connector. Connect a fused jumper wire between fuel pump relay connector cavities No. 30 and 87. Turn ignition on. Using a DVOM, check voltage between ground and fuel pump speed control PWM circuit at PCM harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step  6.
  3. Turn ignition off. Remove fuel pump relay. Connect a fused jumper wire between relay cavities No. 30 and 87. Monitor current between ground and fuel pump speed control PWM driver circuit at PCM harness connector for at least 10 seconds. If reading is between 0.5-1.5 amps, go to step  9. If reading not between 0.5-1.5 amps, go to next step.
  4. Leave jumper wire connected between relay cavities No. 30 and 87. Remove fuel pump speed control relay. Set DVOM to 10-amp scale. Monitor current between fuel pump speed control driver circuit at PCM connector and ground for 10 seconds. If reading is less than 0.5 amps, go to step  10. If reading is not less than 0.5 amps, go to next step.
  5. Locate and repair short to voltage in fuel pump speed control driver circuit. After repairs, go to step  12.
  6. Disconnect fuel pump and fuel pump speed control relay. Connect test light between fuel pump relay connector cavity No. 87 and fuel pump speed control relay connector cavity No. 85. It test light illuminates, go to step  8. If test light does not illuminate, go to next step.
  7. Repair open in fuel pump speed control driver circuit. After repairs, go to step  12.
  8. Repair short to ground in fuel pump speed control driver circuit. After repairs, go to step  12.
  9. Check fuel pump speed control driver circuit for poor connection at PCM. Repair as necessary. After repairs, go to step  12. If connection is okay, go to step  11.
  10. Replace fuel pump speed control relay. After replacing relay, go to step  12.
  11. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  12. Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC FAILED THIS IGN, return to step  2. If scan tool does not indicate that this DTC FAILED THIS IGN, system is okay.
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