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Home >> Suzuki >> 2002 >> XL-7 Plus >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0121: Throttle Position Sensor Circuit - Range/Performance Problem >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

  1. If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK  under SYSTEM TESTS.
  2. Using scan tool, check for current or pending DTC P0122 or P0123. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTCs P0122 and P0123 are not set, go to next step. If DTC P0122 or P0123 is set, perform appropriate test. See DTC P0122  or DTC P0123  .
  3. If using scan tool, go to step  6. If not using scan tool, turn ignition on. Access ECM. ECM is located under instrument panel, behind glove box. See Figure. Backprobing at ECM, measure voltage between ground and ECM connector C51-3 terminal No. 9 (Red/Green wire). See Figure. With throttle closed, voltage should be .5-.9 volts. With throttle fully opened, voltage should be 3.7-4.4 volts. As throttle is opened, voltage should vary between idle specification and wide open throttle. If voltage is as specified, go to next step. If voltage is not as specified, go to step  7.
  4. Turn ignition off. Disconnect ECM 26-pin harness connector C51-3. ECM is located under instrument panel, behind glove box. See Figure. Check for poor terminal contact at ECM harness connector C51-3. If poor terminal contact is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem with wiring is found, go to next step.
  5. Substitute a known good ECM, and repeat DTC CONFIRMATION TEST . If DTC does not reset, testing is complete.
  6. On scan tool, select DATA LIST mode and observe TP SENSOR parameter. With throttle closed, parameter should be .5-.9 volts. With throttle fully opened, parameter should be 3.7-4.4 volts. As throttle is opened, voltage should vary between idle specification and wide open throttle. If voltage is not as specified, go to next step. If readings are as specified, replace ECM and go to DTC CONFIRMATION TEST . If DTC does not reset, testing is complete.
  7. Turn ignition off. Disconnect TP sensor 3-pin harness connector. Check for poor terminal contact at TP sensor connector. If poor terminal contact is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem with wiring is found, go to next step.
  8. Check TP sensor operation. See THROTTLE POSITION SENSOR under SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If TP sensor does not operate as specified, replace as necessary. After repair, repeat DTC CONFIRMATION TEST . If TP sensor operates as specified, go to next step.
  9. Check for high resistance in Gray/Red, Red/Green or Gray/Yellow wire between TP sensor and ECM. See WIRING DIAGRAMS article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem with wiring is found, go to next step.
  10. Substitute a known good ECM, and repeat DTC CONFIRMATION TEST . If DTC does not reset, testing is complete.
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