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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 41 (Engine Controls - Tests W/Codes - 5.9L Gasoline) >> Self-Diagnostic Tests >> Test TC-2A - No Crank Reference Signal At Pcm

Test TC-2A - No Crank Reference Signal At Pcm

WARNING: This page is about a different car, the 1995 Dodge Ram Wagon, 1995 Dodge Ram Van, 1995 Dodge Pickup, and 1995 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION  . For wiring diagram, see WIRING DIAGRAMS  section at the end of this article.
  1. Using scan tool, erase trouble codes. Turn ignition off and then on. Attempt to start engine. If engine will not start, crank engine for at least 10 seconds.
  2. Using scan tool, read trouble codes. If scan tool does not display NO CRANK REFERENCE SIGNAL AT PCM, condition required to set trouble code is not present at this time. Go to next step. If scan tool displays NO CRANK REFERENCE SIGNAL AT PCM, go to step 6).
  3. NO CRANK REFERENCE SIGNAL AT PCM trouble code sets if Powertrain Control Module (PCM) does not see a Crankshaft Position (CKP) sensor signal with Camshaft Position (CMP) sensor signal present or CKP sensor is not present during engine cranking. Possible causes are: open or shorted CKP sensor 8-volt supply circuit (Orange wire), open CKP sensor ground circuit (Black/Light Blue wire), open or shorted CKP sensor signal circuit (Gray/Black wire), improperly adjusted CKP sensor, damaged flywheel, failed CKP sensor or failed PCM. Go to next step.
  4. Inspect all related wiring and connectors, and repair as necessary. Perform TEST VER-2. If no problems are found with wiring and connectors, go to next step.
  5. Start engine. Wiggle wiring harness from CKP sensor to PCM. If engine misfires or stalls, repair wiring harness as necessary. Perform TEST VER-2. If engine does not misfire or stall, see INACTIVE TROUBLE CODE CONDITION  . Perform TEST VER-2. If engine does not misfire or stall, test is complete.
  6. Turn ignition off. Disconnect Crankshaft Position (CKP) sensor connector. Using scan tool in voltmeter mode, check voltage on CKP sensor connector, 8-volt supply circuit (Orange wire). If voltage is less than 7 volts, go to TEST TC-2B.
  7. If voltage is more than 7 volts, connect a jumper wire to CKP sensor signal circuit (Gray/Black wire) on CKP sensor connector harness side.
  8. Using scan tool, read trouble codes. Turn ignition off and then on. Using other end of jumper wire, make and break connection at CKP sensor ground circuit (Black/Light Blue wire) on sensor connector several times while observing scan tool. If scan tool displays NO CAM SYNC SIGNAL AT PCM, replace CKP. Perform TEST VER-2.
  9. If scan tool does not display NO CAM SYNC SIGNAL AT PCM, turn ignition off. Using scan tool in ohmmeter mode, check resistance of CKP sensor connector ground circuit (Black/Light Blue wire). If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform TEST VER-2.
  10. If resistance is less than 5 ohms, disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed-out terminals. Repair as necessary. Perform TEST VER-2. If PCM connector terminals are okay, go to next step.
  11. Using an external ohmmeter, check resistance of CKP signal circuit (Gray/Black wire) between CKP sensor connector harness side and PCM connector terminal No. 24. If resistance is more than 5 ohms, repair open Gray/Black or Red/Light Green wire. Perform TEST VER-2.
  12. If resistance is less than 5 ohms, use scan tool in ohmmeter mode to check resistance of PCM connector terminal No. 24, CKP sensor signal circuit (Gray/Black wire). If resistance is more than 5 ohms, replace PCM. Perform TEST VER-2. If resistance is less than 5 ohms, repair short to ground in Red/Light Green or Gray/Black wire. Perform TEST VER-2.
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