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Home >> Suzuki >> 2003 >> Vitara 2D Utility, 4WD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0123: Throttle Position Sensor Circuit - High Input >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

NOTE: For better performance and results of this diagnostic procedure, usage of appropriate wiring diagram is recommended. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
NOTE: Perform all voltage and resistance tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use an ohmmeter to isolate wiring harness shorts or opens.
  1. If engine system check has been performed, go to next step. If engine system check has not been performed, perform A-4: ENGINE SYSTEM CHECK  under SYSTEM TESTS, then go to next step.
  2. Turn ignition switch to ON position. Using scan tool, check throttle valve opening percentage while depressing accelerator pedal to full throttle position. If scan tool display is zero percent, go to next step. If scan tool display is not zero percent, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. After repair, repeat DTC CONFIRMATION TEST  .
  3. Turn ignition switch to LOCK position. Disconnect TP sensor 3-pin harness connector C30, located on throttle body, see Figure . Check TP sensor and harness connector terminals for corrosion or poor connection. If connector terminals are faulty, repair as necessary and repeat DTC CONFIRMATION TEST  . If connector terminals are okay, turn ignition switch to ON position and measure voltage between TP sensor harness connector C30 terminals No. 1 (Gray/Yellow wire) and No. 3 (Gray/Red wire). See Figure . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, turn ignition switch to LOCK position and disconnect ECM 26-pin harness connector C51-3, located under instrument panel, behind glove box. See Figure . Check ECM sensor and harness connector terminals for corrosion or poor connection. If connector terminals are faulty, repair as necessary and repeat DTC CONFIRMATION TEST  . If connector terminals are okay, check Gray/Red wire for open or short circuit between ECM and TP sensor. If open or short circuit is found, repair as necessary and repeat DTC CONFIRMATION TEST  . If open or short circuit is not found, substitute ECM with a known good unit and repeat DTC CONFIRMATION TEST  .
  4. Measure resistance between TP sensor connector terminals No. 1 and 2 (component test). See Figure . Resistance should vary linearly according to throttle valve opening between 0.02-6.0 k/ohms. Also measure resistance between TP sensor connector terminals No. 1 and 3, resistance should be 4-6 k/ohms. If any resistance is not as specified, replace TP sensor. See THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION article. After repair, repeat DTC CONFIRMATION TEST  . If all resistances are as specified, check for open or short circuit in Red/Green wire between ECM and TP sensor. If open or short circuit is found, repair as necessary and repeat DTC CONFIRMATION TEST  . If open or short circuit is not found, substitute ECM with a known good unit and repeat DTC CONFIRMATION TEST  .
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