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Home >> Suzuki >> 2003 >> XL-7 Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls - Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0121: Throttle Position Sensor - Circuit Range/Performance >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Rodeo Sport and 2002 Isuzu Rodeo. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. With ignition on and engine off, review and record FAILURE RECORDS data on scan tool, then clear DTCs. Operate vehicle within FAILURE RECORDS conditions as specified. Using scan tool, monitor specified DTC information. If scan tool indicates DTC P0121 RAN AND PASSED, check for intermittent problem. See DIAGNOSTIC AIDS  . If scan tool does not indicate DTC P0121 RAN AND PASSED, go to next step.
  3. Turn ignition on. On scan tool, observe TP sensor voltage parameter while moving throttle from closed position to wide open throttle. TP sensor voltage parameter should change smoothly from 0 percent (0.25 volt) to 100 percent (4.75 volts). If parameter changes as specified, go to next step. If parameter does not change as specified, go to step  11 .
  4. Turn ignition off. Disconnect TP sensor 2-pin harness connector. TP sensor is located on throttle body. Start vehicle. Using scan tool, monitor TP sensor signal and voltage parameters. TP sensor parameters at zero percent should hold steady at 0-0.25 volt. If parameters holds as specified, go to step  6 . If parameters do not hold as specified, go to next step.
  5. Turn ignition off. Disconnect PCM Blue 2-pin harness connector C-3. PCM is located under center console in front of shifter. Check for short to voltage in Blue wire (TP sensor input) between PCM and TP sensor. See WIRING DIAGRAMS article. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, leave harness connector disconnected and go to step  12 .
  6. Check for open or short to ground in Blue wire between PCM and TP sensor. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, leave harness connector disconnected and go to next step.
  7. Check for open, short to ground or short to voltage in Red wire between TP sensor and PCM harness connector C-1 terminal A1. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, connect PCM harness connector and go to next step.
  8. Turn ignition off. Using a fused jumper wire, jumper TP sensor harness connector terminals No. 2 (Red wire) and No. 3 (Blue wire). See Fig 1 . On scan tool, monitor TP sensor voltage parameter. Turn ignition on. TP sensor voltage parameter at 100 percent (wide open throttle) should be about 5 volts. If voltage parameter is as specified, go to next step. If voltage parameter is not as specified, go to step  12 .
  9. Turn ignition off. Disconnect PCM White 2-pin harness connector C-2. PCM is located under center console in front of shifter. Check for open, short to ground or short to voltage in Green wire (TP sensor ground) between PCM and TP sensor. See WIRING DIAGRAMS article. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, connect PCM harness connector and go to next step.
  10. Turn ignition off. Using DVOM, measure voltage between TP sensor harness connector terminal No. 1 (Green wire) and No. 2 (Red wire). Turn ignition on. Voltage reading should be about 5 volts. If voltage is as specified, go to next step. If voltage reading is not as specified, go to step  12 .
  11. Replace TP sensor. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, connect PCM harness connector and go to next step.
  12. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT  under POWERTRAIN CONTROL MODULE. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
Fig 1: Identifying Throttle Position Sensor Harness
G00077223Courtesy of ISUZU MOTOR CO.
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