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HOMESERVICE MANUALSCHEVROLET1996CORVETTE BASE, 2D COUPE, 5.7 PREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEBODY, CAB CONTROL SYSTEMSCENTRAL CONTROL MODULEDIAGNOSING & REPAIRING CCM DTCSDTC 51, PASS-KEY(R) INVALID KEY DETECTIONTESTING
1996 Chevrolet Corvette Base, 2D Coupe, 5.7 P

DTC 51, Pass-Key(R) Invalid Key Detection: Testing

1996 Chevrolet Corvette Base, 2D Coupe, 5.7 PSECTION Testing
  1. Try all keys in ignition to find a key that works. Wait 3 minutes between each key for PASS-Key(R) system to reset. If any keys work, replace malfunctioning keys. If no keys work, go to next step.
  2. Check for PASS-Key(R) DTC 52 or 53. DTC 52 or 53 could cause DTC 51 to set. If DTCs 52 and 53 are not present, go to next step. If DTC 52 or 53 is set, diagnose and repair problem, clear DTCs and check for DTC 51. If DTC 51 is set, go to next step.
  3. Using PASS-Key(R) Interrogator (J 35628), determine key code. Turn ignition switch to OFF position. Connect a jumper wire between Data Link Connector (DLC) terminals No. 12 and 5. Turn ignition switch to ON position. Press TRIP/ODO (next test) button on DIC until "1.2" displays on trip monitor. Press ENG/MET (next value) button on DIC until "06xxx" displays on odometer. Note the value of "xxx". Determine key code from value. See KEY CODE IDENTIFICATION table. If key code determined from value indicated on odometer does not match key code displayed on interrogator, go to step 5). If key code determined from value indicated on odometer matches key code displayed on interrogator, go to next step.
    KEY CODE IDENTIFICATION

    "xxx" Value Key Code No.
    33-38 1
    42-47 2
    52-58 3
    64-70 4
    76-83 5
    91-98 6
    106-113 7
    121-128 8
    136-143 9
    149-156 10
    164-170 11
    177-183 12
    188-194 13
    199-204 14
    208-213 15
  4. No problem is present. Check for poor connections at CCM and ignition lock cylinder. Poor connections could cause an open, incorrect PASS-Key(R) resistance or an intermittent fault. If code is set as history, 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.
    WARNING: Vehicle is equipped with air bag supplemental restraint system. When locating 2-pin ignition switch lock cylinder harness connector at base of steering column, DO NOT confuse connector with Yellow 2-pin air bag supplemental restraint system connector also located at base of steering column.
  5. Turn ignition switch to OFF position. Disconnect 2-pin ignition switch lock cylinder harness connector located at base of steering column. Using adapter from Terminal Test Adapter Kit (J 35616-A), connect DVOM between ignition switch lock cylinder harness connector terminal "B" (CCM side of connector) and ground. Turn ignition switch to ON position. Measure voltage. If voltage is about 5 volts, go to step 7). If voltage is not about 5 volts, go to next step.
  6. Using adapter connected to DVOM, backprobe CCM Green connector, terminal E12 to ground and measure voltage. If voltage is not about 5 volts, check for poor connections at CCM. If connections are okay, replace CCM. If voltage is about 5 volts, check for poor connections, shorts or damage in 5-volt PASS-Key(R) input circuit.
  7. Using adapter connected to DVOM, backprobe between ignition switch lock cylinder harness connector terminal "A" (CCM side of connector) and CCM Green connector, terminal F5. Check for continuity. If continuity is present, check for poor connections at CCM. If connections are okay, replace CCM. If continuity is not present, repair PASS-Key(R) ground circuit or connections. If circuit and connections are okay, go to next step.
  8. Check for poor connections at CCM and ignition lock cylinder. Poor connections could cause an open, incorrect PASS-Key(R) resistance or an intermittent fault. If code is set as history, 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.
RENDER: 1.0x

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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.