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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Rodeo Sport, 2002 Isuzu Rodeo, 2002 Isuzu Axiom, and 2002 Honda Passport. 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. Turn ignition on. Using scan tool, observe MAP sensor parameter. If parameter is less than 65 kPa, go to next step. If parameter is not as specified, go to step  6.
    3. NOTE: If parameter does not read 5 volts, check 5-volt reference circuit for EGR valve and Fuel Vapor Pressure (FVP) sensor. See WIRING DIAGRAMS article.
  3. Disconnect MAP sensor 3-pin harness connector. MAP sensor is located at rear of intake manifold. Connect a fused jumper wire between MAP sensor harness connector terminals No. 2 (Red wire) and No. 3 (Black wire). See Figure. On scan tool observe MAP sensor voltage parameter. If MAP sensor voltage parameter is less than 5 volts, go to step  5. If MAP sensor voltage parameter is not as specified, go to next step.
  4. Check for open or short circuit in Red wire (MAP sensor signal circuit) between PCM and MAP 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, go to step  12.
  5. Replace MAP sensor. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  6. Start engine and run until normal operating temperature is achieved (minimum 176°F 80°C). Turn ignition on, engine off. Using scan tool, observe TPS1 and TPS 2 angle parameter while slowly opening throttle. TPS1 angle should increase steadily and smoothly from a closed throttle to wide open throttle as specified. See CHECKING THROTTLE POSITION SENSORS table. If TPS1 and TPS2 operate as specified, check for intermittent problem. See DIAGNOSTIC AIDS . If TPS1 and TPS2 do not operate as specified, go to next step.
    CHECKING THROTTLE POSITION SENSORS

    Throttle Position Sensor Specification (%)
    Throttle Position Sensor No. 1
    Closed Throttle 8-10
    Wide Open Throttle 90-92
    Throttle Position Sensor No. 2
    Closed Throttle 90-92
    Wide Open Throttle 8-10
  7. Turn ignition off. Disconnect TPS 8-pin harness connector. On scan tool, observe TPS voltage parameter. If voltage parameter is about 5 volts, go to next step. If voltage parameter is not as specified, go to step  9.
  8. Connect a test light between TPS harness connector terminals No. 5 (Red wire) and No. 6 (Blue wire). See Fig 1. See WIRING DIAGRAMS article. On scan tool, observe TPS1 voltage parameter. If voltage parameter is about 5 volts, go to step  11. If voltage parameter is not as specified, go to step  10.
  9. Check for short to voltage in Blue wire (TPS1 signal circuit) between TPS1 and PCM. Check for high resistance or poor connection in Green wire (TPS1 sensor ground) between TPS1 and PCM. 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, go to next step.
  10. Check for high resistance or faulty connection in Blue wire (TPS1 signal circuit) between TPS1 and PCM. Check for high resistance or faulty connection in Red wire (TPS1 5-volt reference circuit) between TPS1 and PCM. 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, go to next step.
  11. Replace TPS. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  12. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT  under POWERTRAIN CONTROL MODULE. Use scan tool to clear DTC and verify repair.
Fig 1: Identifying Throttle Position Sensor Harness Connector Terminals
G00077236Courtesy of ISUZU MOTOR CO.
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