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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 39 (Engine Controls - Tests W/Codes - 5.2L CNG) >> Self-Diagnostic Tests >> Test TC-2A - No Crank Reference Signal At Pcm (DTC 11)

Test TC-2A - No Crank Reference Signal At Pcm (DTC 11)

WARNING: This page is about a different car, the 1995 Dodge Ram Wagon, 1995 Dodge Ram Van, 1995 Dodge Pickup, and 1995 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
  1. Using scan tool, erase DTCs. Turn ignition off then on. Attempt to start engine. If necessary, crank engine for up to 10 seconds. Read and record DTCs using scan tool. If scan tool displays NO CRANK REFERENCE SIGNAL AT PCM, go to step 6).
  2. If scan tool does not display NO CRANK REFERENCE SIGNAL AT PCM, condition required to set DTC is not present at this time. NO CRANK REFERENCE SIGNAL AT PCM DTC sets if Powertrain Control Module (PCM) does not see a crank signal with cam signal present.
  3. Possible causes are: open or shorted 8-volt power supply circuit (Orange wire) to Crankshaft Position (CKP) sensor, open or shorted CKP sensor signal circuit (Gray/Black wire), open sensor ground circuit (Black/Light Blue wire), improperly adjusted sensor, failed sensor, or failed PCM. Go to next step.
  4. Inspect all related wiring and connectors, and repair as necessary. Perform TEST VER-2. If wiring and connectors are okay, start engine. Wiggle wiring harness from CKP sensor to PCM. If engine misses or stalls, repair wiring harness where wiggling caused problem to occur. Perform TEST VER-2.
  5. Condition that initially set DTC has just been simulated. Perform following additional checks to assist in identifying a possible intermittent problem. Visually inspect related wiring harness connectors for broken, bent, pushed-out or corroded terminals. Visually inspect related wiring harnesses for chafed, pierced or broken wires. Check all related Tech Service Bulletins (TSBs) and perform corrective action as necessary. Test is complete. Perform TEST VER-2.
  6. Turn ignition off. Disconnect Crankshaft Position (CKP) sensor connector. Using scan tool in ohmmeter mode, check resistance of CKP sensor connector, 8-volt power supply circuit (Orange wire). If resistance is less than 5 ohms, repair short to ground in Orange wire. Perform TEST VER-2.
  7. If resistance is more than 5 ohms, turn ignition on. Using scan tool in voltmeter mode, check voltage on CKP sensor connector, 8-volt power supply circuit (Orange wire). If voltage is less than 7 volts, go to TEST TC-2B.
  8. If voltage is more than 7 volts, connect a jumper wire to CKP sensor connector, CKP sensor signal circuit (Gray/Black wire). Using scan tool, read DTCs. Turn ignition switch to OFF position, then to ON position. While observing scan tool display, tap other lead of jumper to CKP sensor connector, sensor ground circuit (Black/Light Blue wire).
  9. If scan tool displays NO CAM SYNC SIGNAL AT PCM, replace CKP sensor. Perform TEST VER-2. 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, sensor ground circuit (Black/Light Blue wire). If resistance is more than 5 ohms, repair open in Black/Light Blue wire. Perform TEST VER-2.
  10. If resistance is less than 5 ohms, turn ignition off. Disconnect and inspect Powertrain Control Module (PCM) connector for damaged, pushed-out or miswired terminals. If connector is not okay, repair as necessary. Perform TEST VER-2.
  11. If connector is okay, use an external ohmmeter to check resistance of CKP sensor signal circuit (Gray/Black wire) between PCM connector terminal No. 24 and CKP sensor connector. If resistance is more than 5 ohms, repair open in Gray/Black wire. Perform TEST VER-2.
  12. If resistance is less than 5 ohms, put scan tool in ohmmeter mode. Using scan tool, 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 Gray/Black wire or Gray/Violet wire. Perform TEST VER-2.
  13. Using scan tool, read Distributorless Ignition System (DIS) signal status. If scan tool displays NO SIGNAL or CAM ONLY, go to step 17). If scan tool displays CRANK ONLY, go to TEST TC-3A. If scan tool does not display CRANK ONLY, condition required to set DTC is not present at this time. Go to next step.
  14. NO CRANK REFERENCE SIGNAL AT PCM DTC sets if Powertrain Control Module (PCM) does not see a Crankshaft Position (CKP) sensor signal with Camshaft Position (CMP) sensor signal present. Possible causes are: failed CKP sensor, open or shorted CKP sensor signal circuit (Gray/Violet wire), open or shorted CKP sensor 8-volt supply circuit (Orange wire), open CKP sensor ground circuit (Black/Light Blue wire), improperly adjusted CKP sensor, failed Powertrain Control Module (PCM) or failed Transmission Control Module (TCM). Go to next step.
  15. Inspect all related wiring and connectors, and repair as necessary. Perform TEST VER-2. If no problems were found with wiring and connectors, go to next step.
  16. Start engine. Wiggle wiring harness from CKP sensor to Powertrain Control Module (PCM). If engine misfired or stalled, repair wiring harness as necessary. Perform TEST VER-2. If engine did not misfire or stall, see INACTIVE DTC CONDITION  . Perform TEST VER-2.
  17. Turn ignition off. Disconnect Crankshaft Position (CKP) sensor connector. Turn ignition on. 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. If voltage is more than 7 volts, turn ignition off.
  18. Connect a jumper wire between signal circuit (Gray/Violet wire) and ground circuit (Black/Light Blue wire) on CKP sensor connector harness side. Using scan tool, read DIS signal status. Make and break connection at CKP sensor connector several times while observing scan tool.
  19. If scan tool does not display CRANK ONLY, go to next step. If scan tool displays CRANK ONLY, remove CKP sensor. Inspect flywheel for damage. If flywheel is okay, replace CKP sensor. Perform TEST VER-2. If flywheel is damaged, repair as necessary. Perform TEST VER-2.
  20. 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 in Black/Light Blue wire. Perform TEST VER-2.
  21. If resistance is less than 5 ohms, disconnect PCM connector. Inspect PCM sensor connector for damaged or pushed-out terminals. Repair as necessary. Perform TEST VER-2. If PCM connector terminals are okay, go to next step.
  22. Using an external ohmmeter, check resistance of signal circuit (Gray/Violet wire) between CKP sensor connector harness side and PCM connector terminal No. 24. If resistance is more than 5 ohms, repair open in signal circuit Gray/Violet wire. Perform TEST VER-2.
  23. If resistance is less than 5 ohms, Using scan tool in ohmmeter mode, check resistance of CKP sensor connector, signal circuit (Gray/Violet wire). If resistance is more than 5 ohms, replace PCM. Perform TEST VER-2.
  24. If resistance is less than 5 ohms, disconnect Transmission Control Module (TCM) connector. Using scan tool, check resistance of CKP sensor connector, signal circuit (Gray/Violet wire). If resistance is more than 5 ohms, replace TCM. Perform TEST VER-2. If resistance is less than 5 ohms, repair short to ground in Gray/Violet wire. Perform TEST VER-2.
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