LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2001 >> Cherokee Classic, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1685: Invalid Skim Key >> Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P1685: Invalid Skim Key: Testing

  1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P1685 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1685 or displayed count is not "0", go to step  7 .
  2. Using scan tool, attempt to communicate with SKIM. If scan tool communicates with SKIM, go to next step. If scan tool does not communicate with SKIM, check for open bus circuits between data link connector and SKIM. Also check power and ground circuits to SKIM. See NO RESPONSE FROM SENTRY KEY IMMOBILIZER MODULE under SYSTEM TESTS in BODY CONTROL MODULES - CHEROKEE article in ACCESSORIES & EQUIPMENT. Repair wiring as necessary.
  3. Using scan tool, check for SKIM DTCs. If no DTCs are present, go to next step. If any DTCs are present, repair SKIM DTCs before continuing with this test. See BODY CONTROL MODULES - CHEROKEE article in ACCESSORIES & EQUIPMENT.
  4. Using scan tool, display Vehicle Identification Number (VIN) that is programmed into PCM. If VIN is programmed into PCM, go to next step. If VIN has not been programmed into PCM, use scan tool and program VIN into PCM and retest.
  5. Using scan tool, display VIN that is programmed into PCM. If correct VIN is displayed, go to next step. If correct VIN is not displayed, replace PCM.
  6. Turn ignition off. Replace SKIM and program new SKIM. See REMOVAL & INSTALLATION in BODY CONTROL MODULES - CHEROKEE article in ACCESSORIES & EQUIPMENT. Attempt to start engine. Using scan tool, read PCM DTCs. If DTC P1685: INVALID SKIM KEY resets, replace PCM. If DTC P1685: INVALID SKIM KEY does not reset, no problem is indicated at this time. Test is complete.
  7. DTC P1685 may have been set if SKIM was disconnected or recently replaced. All customer's ignition keys for this vehicle must be tested at this time. Turn ignition off and remove ignition key. Using another customer key, turn ignition on and attempt to start engine. If engine starts, this usually indicates a good key. Continue using remaining ignition keys. Using scan tool, check for DTCs. If all keys start engine and DTC P1685: INVALID SKIM KEY does not reset, no problem is indicated at this time. Problem may have been an actual theft attempt. Test is complete. If any key does not start engine, replace ignition key that would not start engine. Program new key. See SENTRY KEYS under PROGRAMMING in BODY CONTROL MODULES - CHEROKEE article in ACCESSORIES & EQUIPMENT.
scientia non olet · About LEMON Manuals