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Home >> Jeep >> 1996 >> Grand Cherokee Limited, 5.2 Y >> Repair and Diagnosis >> External Pages >> Different car >> Section 180 (Engine Controls - Tests W/Codes - 4.0L) >> Self-Diagnostic Tests >> Test TC-7A - No Vehicle Speed Sensor Signal (DTC 15)

Test TC-7A - No Vehicle Speed Sensor Signal (DTC 15)

WARNING: This page is about a different car, the 1995 Jeep Wrangler, 1995 Jeep Grand Cherokee, and 1995 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Perform TEST TC-1A  before proceeding with this test. For connector terminal identification, see CONNECTOR IDENTIFICATION  at beginning of article. For wiring diagrams, see WIRING DIAGRAMS  at the end of this article. Perform TEST VER-2A  after each repair.
  1. Raise vehicle so drive wheels are free to spin. Start engine. Using scan tool, read Vehicle Speed Sensor (VSS) signal. Put transmission in any forward gear and allow engine to idle. If scan tool displays more than zero MPH, go to next step. If scan tool does not display more than zero MPH, go to step 4).
  2. Condition required to set trouble code message is not present at this time. NO VEHICLE SPEED SENSOR SIGNAL trouble code message sets if Powertrain Control Module (PCM) does not see a VSS signal for more than 11 seconds at PCM terminal No. 47 (White/Orange wire) under road load conditions. Possible causes are: open or shorted VSS signal circuit (White/Orange wire), open VSS sensor 8-volt supply circuit (Orange wire on XJ and YJ bodies or White/Black wire on ZJ body), open VSS sensor ground circuit (Black/Light Blue wire), failed VSS sensor, failed Daytime Running Light (DRL) module (if equipped), speedometer pinion damaged, or failed PCM. Go to next step.
  3. Inspect all related wiring and connectors and repair as necessary. If no problems were found with wiring and connectors, see INACTIVE DTC CONDITION  in this article. Test is complete.
  4. Turn ignition off. Disconnect Vehicle Speed Sensor (VSS) connector and ensure connector is clean and not damaged. Turn ignition on. Using scan tool in voltmeter mode, check voltage on VSS sensor connector, 8-volt supply circuit (Orange wire on XJ and YJ bodies or White/Black wire on ZJ body). If voltage is more than 7 volts, go to next step. If voltage is less than 7 volts, repair open in Orange wire on XJ and YJ bodies or White/Black wire on ZJ body.
  5. Using scan tool in voltmeter mode, check voltage on VSS sensor connector, signal circuit (White/Orange wire). If voltage is less than 4 volts, go to TEST TC-7B  . If voltage is more than 4 volts, turn ignition off. Connect a jumper wire between VSS signal circuit (White/Orange wire) and ground circuit (Black/Light Blue wire) at VSS sensor connector.
  6. Turn ignition on. Using scan tool, read vehicle speed. Make and break connection at VSS sensor connector several times while observing scan tool display. If scan tool displays vehicle speed as more than zero MPH, replace VSS. If scan tool does not display more than zero MPH, go to next step.
  7. Turn ignition off. Using scan tool in ohmmeter mode, check resistance on VSS sensor connector, ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/Light Blue wire.
  8. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector and ensure connector is clean and not damaged. Using an external ohmmeter, check resistance of signal circuit (White/Orange wire) between VSS connector harness side and PCM connector terminal No. 47. If resistance is more than 5 ohms, repair open in White/Orange wire. If resistance is less than 5 ohms, replace PCM.
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