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Test TC-87A: Speed Control Switch Always Low

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
  1. Using scan tool, record all DTCs. Erase DTCs. Turn ignition on. Using scan tool, read Speed Control (S/C) switch sensor voltage. If voltage is one volt or more on AB body or 4.5 volts or more on all other bodies, go next step. If voltage is less than one volt on AB body or less than 4.5 volts on all other bodies, go to step 3)  .
  2. Condition required to set DTC is not present at this time. SPEED CONTROL SWITCHES DTC sets if Powertrain Control Module (PCM) senses switch voltage less than one volt on AB body or less than 4.5 volts on all other bodies, for 2 minutes. Possible causes are: shorted switch circuit, defective PCM, open switch ground circuit or shorted or open switch. See INACTIVE DTC CONDITION . Test is complete. Perform TEST VER-4A: SPEED CONTROL VERIFICATION .
  3. Disconnect S/C on/off switch connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If connector and terminals are okay, go to next step.
  4. Read S/C switch sensor voltage. If voltage changes to 5 volts, replace S/C on/off switch and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If voltage does not change to 5 volts, go to next step.
  5. Disconnect S/C cancel switch connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If connector and terminals are okay, go to next step.
  6. Read S/C switch sensor voltage. If voltage changes to 5 volts, replace S/C cancel switch and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If voltage does not change to 5 volts, go to next step.
  7. On AB body, go to next step. On all other bodies, turn ignition off. Using an external ohmmeter, check resistance between S/C switch connector, S/C signal circuit (Red/Light Green wire on TJ and XJ bodies; Yellow/Red wire on ZJ body; White wire on all other bodies) and sensor ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, repair S/C signal circuit shorted to ground circuit and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If resistance is 5 ohms or more, go to next step.
  8. Ensure ignition is off. Disconnect Powertrain Control Module (PCM) connectors. Inspect connectors and terminals for damage. Repair connectors and terminals as necessary and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If connectors and terminals are okay on AB body, go to next step. On all other bodies, go to step 10)  .
  9. Using an external ohmmeter, check resistance between S/C switch connector, S/C signal circuit (White wire) and sensor ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, repair S/C signal circuit for a short to ground circuit and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If resistance is 5 ohms or more, go to next step.
  10. Using an external ohmmeter, check resistance between PCM Gray connector, S/C switch signal circuit (White/Light Green wire on AB body; Gray/Light Blue wire on AN body; Brown/Yellow wire on DN body; Pink wire on ZJ body; Red/Light Green wire on all other bodies) and PCM Black connector, ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, repair S/C switch signal circuit for a short to ground circuit and perform TEST VER-4A: SPEED CONTROL VERIFICATION . If resistance is 5 ohms or more, replace PCM and perform TEST VER-4A: SPEED CONTROL VERIFICATION .
NOTE: A break in test sequence occurs at this point. Sequence skips from TEST TC-87A to TEST TC-101A. No tests have been omitted.
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