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Home >> Mazda >> 2001 >> B2500 SE, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> System Tests >> Test DH: Throttle Position Sensor >> Diagnostic Aids
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Diagnostic Aids

Perform this test only when directed by QUICK TEST. This test is intended to diagnose the following:

Normal range of throttle angle measurement for TP sensor is 0-96.6 degrees. To pass QUICK TEST  procedure, range of throttle rotation (in degrees) must be within 3 percent of specification. To prevent replacement of good components, be aware the following non-EEC related areas may be at fault:

  1. 1) KOEO & KOER DTC P1124: Check For Other DTCs

    DTC P1124 is set when TP sensor rotation angle or voltage reading is less than 13.27 percent (.66 volt) or is more than 23.52 percent (1.17 volt) during KOEO or KOER self-test. Possible causes for this fault are:
    • Binding Or Bent Throttle Linkage
    • TP Sensor Not Seated Properly
    • Throttle Plate Below Closed Throttle Position
    • Throttle Plate Screw Misadjusted
    • Faulty TP Sensor
    • Faulty Powertrain Control Module (PCM)

    Perform KOEO ON-DEMAND SELF-TEST  and KOER ON-DEMAND SELF-TEST . Check for DTC P1400. If DTC P1400 is present along with P1124, go to TEST HE, step  1). If DTC P1400 is not present with DTC P1124, go to next step.

  2. 2) Check For Binding Throttle Plate Or Linkage

    Inspect throttle body for binding. If throttle body is binding, check for binding throttle or cruise control linkage, vacuum line or harness interference. Repair as necessary. If throttle moves freely, opens fully and returns to closed throttle position and no mechanical problem is found, go to step  8).

  3. 3) DTC P1120: Check For Frayed Wires Or Corrosion On Connector Terminals

    DTC P1120 is set when TP sensor rotation angle or voltage reading remains within calibrated range but falls between 3.42-9.85 percent (.17-.49 volt) during KOEO or KOER self-test. Possible causes for this fault are:
    • Frayed Or Corroded Circuit Wires Or Connectors
    • VREF Circuit Open To TP
    • VREF Circuit Shorted To SIG RTN Circuit
    • Loose Connector Or Terminals At TP Sensor

    Inspect TP sensor connector for loose, damaged or corroded terminals. Inspect wiring harness between TP sensor and PCM for damage or corrosion. Repair as necessary. If no problem is found, go to next step.

  4. 4) Check For Stuck TP Sensor

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. While observing TP V PID, slowly move throttle through range from closed to wide open throttle. If TP V PID value indicates a sudden drop below 9.85 percent (.49 volt), go to next step. If TP V PID value increases and decreased gradually and smoothly, go to step  20).

  5. 5) Check Voltage Between VREF & SIG RTN Circuits To TP Sensor

    Turn ignition switch to OFF position. Disconnect TP sensor connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN terminals at TP sensor harness connector. See Fig 1 or Fig 2 . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, reconnect TP sensor and go to TEST C, step  1).
    Fig 1: Identifying TP Sensor Circuits & Connector Terminals (Except B2300)
    G99J02598Courtesy of FORD MOTOR CO.
    Fig 2: Identifying TP Sensor Circuits & Connector Terminals (B2300)
    G00013241Courtesy of FORD MOTOR CO.

  6. 6) Check TP Circuit For Open

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals and repair as necessary. Using a DVOM, measure resistance of TP circuit between PCM harness connector TP terminal and TP sensor harness connector TP terminal. See Fig 1 or Fig 2 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in TP circuit.

  7. 7) Check TP Sensor Voltage To PCM

    Reconnect PCM harness connector(s). Start engine and idle for 2 minutes. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. While observing TP V PID, slowly open throttle. If at any time TP V PID voltage falls between 3.42-9.85 percent (.17-.49 volt) range, replace TP sensor. If voltage does not fall between 3.42-9.85 percent (.17-.49 volt) range, repeat QUICK TEST . If DTC P1120 is still present, go to step  20).

  8. 8) DTC P0123 Or P1124: Simulate Opposite TP Sensor PID Reading

    This DTC indicates TP sensor rotation angle or voltage exceeded maximum calibrated limit during KOEO or KOER self-test. Possible causes for this fault are:
    • TP Sensor Not Seated Fully
    • TP Circuit Shorted To VPWR
    • VREF Circuit Shorted To VPWR
    • SIG RTN Circuit Open To TP Sensor
    • Faulty TP Sensor
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect TP sensor connector. Inspect connector for loose, damaged or corroded terminals and repair as necessary. Turn ignition switch to ON position. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. If TP V PID voltage is 3.42 percent (.17 volt) or more, go to step  10). If TP V PID voltage is less than 3.42 percent (.17 volt), go to next step.

  9. 9) Check Voltage Between VREF & SIG RTN Circuits To TP Sensor

    Using a DVOM, measure voltage between TP sensor harness connector VREF and SIG RTN terminals. See Fig 1 or Fig 2 . If voltage is 4-6 volts, replace TP sensor. If voltage is not 4-6 volts, reconnect components and go to TEST C, step  1).

  10. 10) Check TP Circuit For Short To VREF Or VPWR Circuits

    Turn ignition switch to OFF position. Leave TP sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals and repair as necessary. Using a DVOM, measure resistance between PCM harness connector TP terminal and both VPWR and VREF terminals. If any resistance measurement is 10 k/ohms or less, repair short in affected circuit. If all resistance measurements are more than 10 k/ohms, replace PCM.

  11. 11) DTC P0122: Simulate Opposite TP Sensor PID Reading

    This DTC indicates TP sensor rotation angle or voltage fell below minimum calibrated limit during KOEO or KOER self-test. Possible causes for this fault are:
    • TP Sensor Not Seated Fully
    • TP Circuit Open To PCM
    • VREF Circuit Open To TP Sensor
    • TP Circuit Shorted To SIG RTN Or PWR GND
    • Faulty TP Sensor
    • Faulty PCM
    NOTE: An intermittent fault can cause a Continuous Memory DTC P0122. If a Continuous Memory DTC P0122 is still present after performing steps 11) through 14), go to TEST Z, step  1) for intermittent testing.

    Turn ignition switch to OFF position. Disconnect TP sensor connector. Inspect connector for loose, damaged or corroded terminals and repair as necessary. Connect a jumper wire between TP harness connector VREF and TP terminals. Turn ignition switch to ON position.

    NOTE: If communication link error is displayed, remove jumper wire and go to step  14).

    Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. If TP V PID voltage is more than 9.3 percent (4.65 volts), replace TP sensor. If PID voltage is 9.3 percent (4.65 volts) or less, remove jumper wire and go to next step.

  12. 12) Check Voltage Between VREF & SIG RTN Circuits

    Turn ignition switch to ON position. Using a DVOM, measure voltage between TP sensor harness connector VREF and SIG RTN terminals. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, reconnect sensor and go to TEST C, step  1).

  13. 13) Check TP Circuit For Open

    Turn ignition switch to OFF position. Leave TP sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals and repair as necessary. Using a DVOM, measure resistance between PCM harness connector TP terminal and TP sensor harness connector TP terminal. See Fig 1 or Fig 2 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in TP circuit.

  14. 14) Check TP Circuit For Short To SIG RTN Or PWR GND

    Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between PCM harness connector TP terminal and both SIG RTN and PWR GND terminals. If either resistance measurement is 10 k/ohms or less, repair short in affected circuit. If both resistance measurements are more than 10 k/ohms, replace PCM.

  15. 15) KOER & Continuous Memory DTC P1121: Check Rationality Between TP & MAF Sensors

    This DTC is set when the comparison between TP and MAF sensor readings are not consistent with calibrated load values during KOER self-test. Possible causes for this fault are:
    • Air Leak Between MAF Sensor & Throttle Body
    • TP Sensor Not Seated Fully
    • Faulty TP Sensor
    • Faulty MAF Sensor

    Attempt to start engine. If engine will start, go to next step. If engine will not start, check for cracks or openings in air induction system between MAF sensor and throttle body. Repair as necessary. If air induction system is okay, go to TEST A, step  1).

  16. 16) Check Mechanical Operation Of TP Sensor

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. While observing TP V PID voltage, slowly move throttle through range from closed position to wide open throttle. If TP V PID voltage changes from 9.85-93.00 percent (.49-4.65 volts), go to next step. If TP V PID voltage does not change from 9.85-93.00 percent (.49-4.65 volts), replace TP sensor. Repeat QUICK TEST  to verify repair.

  17. 17) Check TP Sensor Signal While Driving Vehicle

    Drive vehicle (vary throttle position) while selecting TP V PID and LOAD PID from PID/DATA MONITOR & RECORD menu. If TP V PID voltage is 49.02 percent (2.44 volts) or less and LOAD PID value is 30 percent or more, go to next step. If TP V PID voltage is more than 49.02 percent (2.44 volts) and LOAD PID value is less than 30 percent, check for cracks or openings in air induction system between MAF sensor and throttle body. For air restrictions, go to TEST HU, step  1). If air induction system is okay, replace TP sensor.

  18. 18) Check TP Sensor Signal With Engine Under Load

    Start engine and allow to idle. If engine does not start, go to TEST A, step  1). Drive vehicle (vary throttle position) in higher gears (preferably Overdrive) while selecting TP V PID and LOAD PID from PID/DATA MONITOR & RECORD menu. If TP V PID is 4.82 percent (.24 volt) or more and LOAD PID is 55 percent or less, fault is intermittent and cannot be duplicated at this time. Testing is complete. If TP V PID is less than 4.82 percent (.24 volt) and LOAD PID is more than 55 percent, tighten TP sensor (if necessary). Clear DTCs. Perform test drive utilizing all phases of vehicle operation. Perform QUICK TEST . If DTC Continuous Memory P1121 is still present, replace MAF sensor.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 18) to step 20). No test procedures have been omitted.

  19. 20) Continuous Memory DTCs P1120 Or P1125: Check For Intermittent TP Circuit Signal

    These DTCs are set when TP sensor voltage reading falls below minimum calibrated range of .49 volt or exceeded maximum calibrated range of 4.65 volts during the last 80 drive cycles. Possible causes for this fault are:
    • Poor Continuity Through TP Sensor Wiring Harness Or Connector
    • Intermittent Open Or Short In TP Sensor

    Ensure scan tool is connected to Data Link Connector (DLC). Start engine and allow to idle. Raise engine speed to 1500 RPM for 5 seconds and return to idle. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. While observing TP V PID, lightly tap on TP sensor and wiggle sensor connector and wiring harness to simulate road shock. If TP V PID voltage stays within normal operating range of 9.85-93.00 percent (.49-4.65 volts), go to next step. If TP V PID voltage does not stay within normal operating range of 9.85-93.00 percent (.49-4.65 volts), inspect TP sensor installation and connector. Repair as necessary and retest. If TP sensor installation and connector are okay, replace TP sensor.

  20. 21) Check TP Sensor Wiring Harness For Intermittent Opens Or Shorts

    Turn ignition switch to OFF position. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. Turn ignition switch to ON position. While observing TP V PID, wiggle small sections of wiring harness starting at the TP sensor working toward PCM. If TP V PID voltage stays within normal operating range of 9.85-93.00 percent (.49-4.65 volts), problem is intermittent and cannot be identified at this time. Go to TEST Z, step  1). If PID voltage does not stay within normal operating range of 9.85-93.00 percent (.49-4.65 volts), isolate fault and repair as necessary.
    21. NOTE: If KOER ON-DEMAND SELF-TEST terminates when placing gear selector lever into Drive or Reverse, go to step  25).

  21. 22) KOER & Continuous Memory DTC P0121: Verify KOER On-Demand Self-Test Completion
    Start engine and allow to idle. Using scan tool, enter KOER ON-DEMAND SELF-TEST . Attempt to drive vehicle while still in KOER ON-DEMAND SELF-TEST. Turn ignition switch to OFF position and wait 15 seconds. Start engine again. Repeat KOER ON-DEMAND SELF-TEST . If DTC P0121 is still present or KOER ON-DEMAND SELF-TEST does not terminate, go to next step. If KOER ON-DEMAND SELF-TEST terminates and DTC P0121 is not present, problem is intermittent and cannot be identified at this time.
    22. CAUTION: DO NOT clean throttle bore or plate area. Cleaning will damage throttle body assembly.

  22. 23) Isolate Binding Or Sticking Problem
    Disconnect accelerator and speed control cables from throttle body linkage. Rotate linkage on throttle body. If sticking, binding or grabbing is felt when rotating throttle body linkage, replace throttle body assembly. If throttle body linkage rotates freely without sticking, binding or grabbing, replace faulty cable(s). Repeat QUICK TEST . If DTC P0121 is still present, go to next step.

  23. 24) Check TP Sensor Mechanical Operation

    Turn ignition switch to ON position. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. While observing TP V PID voltage, slowly move throttle through range from closed position to wide open throttle. If TP V PID voltage increases smoothly during throttle movement, problem cannot be identified at this time. If TP V PID voltage does not increase smoothly during throttle movement, turn ignition switch to OFF position and replace TP sensor.

  24. 25) Check TP & SIG RTN Circuit For Opens

    Turn ignition switch to OFF position. Disconnect PCM connector(s) and TP sensor connector. Using a DVOM, measure resistance of TP circuit between PCM harness connector terminal and TP sensor harness connector terminal. See Fig 1 or Fig 2 . Using a DVOM, measure resistance of SIG RTN circuit between PCM harness connector terminal and TP sensor harness connector terminal. If each resistance measurement is less than .5 ohm, replace TP sensor. Repeat QUICK TEST  to verify repair. If either resistance measurement is .5 ohm or more, repair open in affected circuit. Repeat QUICK TEST  to verify repair.
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