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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 47 (Engine Controls - Tests W/Codes - 5.9L Diesel) >> Self-Diagnostic Tests >> Test TC-11A - No Crank Reference Signal At Pcm

Test TC-11A - No Crank Reference Signal At Pcm

WARNING: This page is about a different car, the 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 diagrams, see WIRING DIAGRAMS  section at the end of this article.
  1. Using scan tool, select SENSOR TESTS. Start engine. Using scan tool, read engine RPM. If scan tool does not show an RPM reading, go to step 4). If scan tool shows a RPM reading, condition required to set DTC is not present at this time. Go to next step.
  2. NO CRANK REFERENCE SIGNAL AT PCM DTC sets if no signal is present during load conditions with vehicle speed more than 10 MPH. Possible causes are: open or shorted 8-volt supply circuit (Orange wire), open or shorted Crankshaft (CKP) signal circuit (Gray/Black wire), open sensor ground (Black/Light Blue wire), failed CKP sensor, or failed PCM.
  3. Inspect wiring and connectors. Repair harness or connector as necessary. Perform TEST VER-1. If no problems are found with wiring and connectors, wiggle harness between PCM 6and sensor while observing RPM reading on scan tool. If RPM becomes erratic or stops, repair appropriate harness or connector. Perform TEST VER-1. If RPM does not become erratic or stop, see INACTIVE DTC CONDITION  . Test is complete. Perform TEST VER-1.
  4. 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-11B.
  5. If voltage is more than 7 volts, connect a jumper wire to CKP sensor connector signal circuit (Gray/Black wire). Using scan tool, read RPM while tapping other end of jumper wire to sensor ground circuit (Black/Light Blue wire). If scan tool shows an RPM reading, replace CKP sensor. Perform TEST VER-1.
  6. If scan tool does not show RPM reading, turn ignition off. Using scan tool in ohmmeter mode, check resistance of CKP sensor ground circuit (Black/Light Blue wire). If resistance is 5 ohms or more, repair Black/Light Blue wire for an open circuit to wiring harness splice. Perform TEST VER-1.
  7. If resistance is less than 5 ohms, disconnect PCM connector. Check connector and repair as necessary. Perform TEST VER-1. If connector is okay, use an external ohmmeter to check resistance of CKP sensor signal circuit (Gray/Black wire). If resistance is more than 5 ohms, replace PCM. Perform TEST VER-1. If resistance is less than 5 ohms, repair short to ground in Gray/Black wire. Perform TEST VER-1.
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