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P1688 Internal Fuel Injection Pump Failure

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Mopar1973Man

By Mopar1973Man

DTC P1688: INTERNAL FUEL INJECTION PUMP FAILURE

Monitor & Set Conditions

Fuel Pump Control Module (FPCM) is monitored with ignition on engine off, and with engine running. DTC may set if FPCM, PCM memory, programming or hardware error is detected.

Possible Causes

  • Good Trip Counter Equals Zero
  • Fuel Pump Control Module (FPCM)

Testing

1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1688 is displayed and not equal to zero, go to next step. If Good Trip Counter for DTC P1688 is displayed and equal to zero, replace FPCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.

2. Ensure ignition is on with engine off. Using scan tool, check for DTCs and record FREEZE FRAME data. Try to duplicate conditions recorded in FREEZE FRAME data. Using scan tool, check for DTCs. If DTC P1688 returns, replace fuel injection pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If DTC P1688 does not return, test is complete.

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