LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 1998 >> Wrangler Sahara, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Engine Performance >> Self-Diagnostic Tests >> Test TC-166A: Low Output Speed Sensor Rpm Above 15 Mph
September 30: LEMON manuals is back up on a temporary server! Slowness is possible

Test TC-166A: Low Output Speed Sensor Rpm Above 15 Mph

NOTE: This test does not apply to TJ and XJ bodies. For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
  1. Using scan tool, read DTCs. On all bodies except AB body, go to next step. On AB body, if DTC SPECIFIC GOOD TRIPS counter is not displayed or displayed count is not "0", perform TEST TC-166B: LOW OUTPUT SPEED SENSOR RPM ABOVE 15 MPH . If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed count is "0", indicating DTC still exists, go to next step.
  2. If P/N SWITCH STUCK IN PARK OR IN GEAR DTC is present, repair this DTC before proceeding. If DTC is not present, go to next step.
    WARNING: Keep hands and feet clear of rotating wheels.
  3. Raise and support vehicle so drive wheels are free to rotate. Start engine. Using scan tool, read Output Speed Sensor (OSS) signal. Place transmission in any forward gear. On AB body, go to next step. On all other bodies, go to step 5)  .
  4. Release brakes and allow wheels to rotate. If scan tool displays 60 MPH or less, go to step 10)  . If scan tool displays more than 60 MPH, go to step 6)  .
  5. Accelerate to 20 MPH. If scan tool does not display engine speed more than 400 RPM, go to step 10)  . If scan tool displays engine speed more than more than 400 RPM, go to next step.
  6. Maintain 20 MPH. While monitoring OSS signal, wiggle connectors and wiring harness from OSS to Powertrain Control Module (PCM). If reading drops toward zero MPH while wiggling connectors and harness, repair connector or harness that caused drop and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If reading does not change, go to next step.
  7. Using scan tool, erase DTCs. Road test vehicle. Using scan tool, read DTCs. If LOW OUTPUT SPEED SENSOR DTC does not return on AB body, perform TEST TC-166B. On all other bodies, go to step 9)  . If DTC returns, go to next step.
  8. Replace OSS. Using scan tool, erase DTCs. Road test vehicle. Using scan tool, read DTCs. If LOW OUTPUT SPEED SENSOR DTC does not return, test is complete. Perform TEST VER-2A: ROAD TEST VERIFICATION . If DTC returns, replace PCM and perform TEST VER-2A: ROAD TEST VERIFICATION .
  9. Condition required to set DTC is not present at this time. LOW OUTPUT SPEED SENSOR RPM DTC sets if no OSS signal (23 pulses per output shaft revolution) is received at PCM. Possible causes are: defective OSS, defective connections, no pulses, defective wiring, or defective PCM. Test is complete.
  10. Turn ignition off. Disconnect Powertrain Control Module (PCM) connectors. Inspect connectors and terminals for damage. Repair connectors and terminals as necessary and perform TEST VER-2A: ROAD TEST VERIFICATION . If connectors and terminals are okay, go to next step.
  11. Using an external ohmmeter, check resistance between ground and PCM White connector, OSS signal circuit (Light Green/Black wire on BE/BR bodies; Light Green/White wire on all other bodies). If resistance is less than 5 ohms, repair OSS signal circuit for short to ground and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If resistance is 5 ohms or more, go to next step.
  12. Check resistance between ground and PCM White connector, ground circuit (Dark Blue/Black wire). If resistance is 5 ohms or less, repair ground circuit for short to ground and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If resistance is more than 5 ohms, go to next step.
  13. Check resistance between PCM White connector, OSS signal circuit (Light Green/Black wire on BE/BR bodies; Light Green/White wire on all other bodies) and ground circuit (Dark Blue/Black wire). If resistance is 300-1200 ohms, replace PCM and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If resistance is not as specified, go to next step.
  14. Disconnect OSS connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If connector and terminals are okay, go to next step.
  15. Check resistance across OSS connector. If resistance is not 300-1200 ohms, replace OSS and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, orTEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If resistance is as specified, go to next step.
  16. Check resistance of OSS signal circuit (Light Green/Black wire on BE/BR bodies; Light Green/White wire on all other bodies) between PCM white connector and OSS connector. If resistance is more than 5 ohms, repair open OSS signal circuit and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If resistance is 5 ohms or less, repair open OSS ground circuit and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies.
scientia non olet · About LEMON Manuals