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Home >> Mazda >> 2013 >> 5 Grand Touring >> Repair and Diagnosis >> External Pages >> Different car >> Section 46 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0121, DTC P0122, DTC P0123, DTC P1120, DTC P1121, DTC P1124 Or DTC P1125 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed:
    • For KOEO and KOER DTC P1124, go to step  2 .
    • For DTC P1120, go to step  4 .
    • For DTC P0123, go to step  9 .
    • For Continuous Memory DTC P1124, go to step  9 .
    • For DTC P0122, go to step  13 .
    • For DTC P1121, go to step  17 .
    • For DTC P1125, go to step  21 .
    • For DTC P0121, go to step  23 .

  2. Check For DTC P1400 In KOEO Or KOER Self-Test

    If KOEO or KOER DTC P1400 is set with P1124, go to DTC P1400  . If KOEO or KOER DTC P1400 is not set with P1124, go to next step.

  3. Check For Stuck Throttle Plate Or Linkage

    Visually inspect throttle linkage and throttle plate for binding or sticking. Verify throttle plate and linkage is at closed throttle position. If throttle moves freely and returns to closed throttle position, go to step  9 . If throttle does not move freely and does not return to closed throttle position, repair or replace as necessary. Go to step  25 .

  4. DTC P1120: Check TP Circuit For Frayed Wires Or Corrosion On Connectors

    Visually inspect TP sensor harness connector pins for corrosion. Visually inspect harness wires between TP sensor and PCM for insulation fraying and corrosion. If connector and harness are okay, go to next step. If connector and harness are not okay, repair as necessary. Go to step  25 .

  5. Check For Stuck TP Sensor

    With KOEO, access TP V PID. Slowly move throttle from closed throttle position to wide open throttle position and observe TP V PID. If voltage is less than 0.49 volt, go to next step. If voltage is 0.49 volt or more, go to step  21 .

  6. Check VREF & SIG RTN Circuit To TP Sensor

    Turn ignition off. Disconnect TP sensor. With KOEO, measure voltage between VREF circuit (Brown/White wire) and SIG RTN circuit (Gray/Red wire) at TP sensor harness connector. See Fig 1 . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, restore all electrical connections. Go to VEHICLE REFERENCE VOLTAGE  under SYSTEM TESTS.
    Fig 1: Identifying TP Sensor Circuits
    G00155530Courtesy of MAZDA MOTORS CORP.

  7. Check TP Circuit Resistance

    Turn ignition off. Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance of TP circuit between breakout box terminal No. 89 and TP sensor harness connector (Gray/White wire). See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. Go to step  25 .

  8. Check TP Sensor Signal To PCM

    Connect PCM to breakout box. Reconnect TP sensor connector. Start engine and idle for 2 minutes. Access TP V PID. While observing TP V PID, slowly open throttle. If voltage is 0.17-0.49 volts at any time, replace faulty TP sensor. Go to step  25 . If voltage is not 0.17-0.49 volts at any time, rerun KOEO and KOER test. If DTC P1120 is still present, go to step  21 .

  9. DTCs P0123 Or P0124: Attempt To Generate The Opposite Throttle Position Angle (Voltage) PID Reading

    An intermittent may cause DTC P0123. If DTC P0123 is still set after performing steps  9 through  12 , go to step  21 . If DTC P0123 is not set after performing steps  9 through  12 , turn ignition off. Disconnect TP sensor. With KOEO, access TP V PID. Observe voltage. If voltage is less than 0.17 volt, go to next step. If voltage is 0.17 volt or more, go to step  12 .

  10. Check SIG RTN Circuit For Open

    Turn ignition off. Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance of SIG RTN circuit (Gray/Red wire) between breakout box terminal No. 91 and TP sensor harness connector. See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. See WIRING DIAGRAMS article. Go to step  25 .

  11. Check VREF & SIG RTN Circuits To TP Sensor

    With KOEO, measure voltage between VREF circuit (Brown/White wire) and SIG RTN circuit (Gray/Red wire) at TP sensor harness connector. See Fig 1 . If voltage is 4-6 volts, replace faulty TP sensor. Go to step  25 . If voltage is not 4-6 volts, restore all electrical connections. Go to VEHICLE REFERENCE VOLTAGE  under SYSTEM TESTS.

  12. Check TP Circuit For Shorts To VREF Or VPWR In Harness

    Turn ignition off. Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance between breakout box terminal No. 89 (TP circuit) and terminals No. 71 or 97 (VPWR circuit). Record reading. Measure resistance between breakout box terminals No. 89 (TP circuit) and 90 (VREF circuit). Record reading. If either resistance measurement is more than 10,000 ohms, replace faulty PCM. Go to step  25 . If either resistance measurement is 10,000 ohms or less, repair short circuit in harness. See WIRING DIAGRAMS article. Go to step  25 .

  13. DTC P0122: Attempt To Generate The Opposite Throttle Position Angle (Voltage) PID Reading

    An intermittent fault may cause Continuous Memory DTC P0122. If DTC P0122 is still set after performing steps  13 through  16 , go to step  21 . Turn ignition off. Disconnect TP sensor. Jumper VREF circuit (Brown/White wire) and TP circuit (Gray/White wire) at TP sensor harness connector. See Fig 1 . With KOEO, access TP V PID. If a scan tool communication concern is present, remove jumper wire. Go to step  16 . If voltage is more than 4.65 volts, replace faulty TP sensor. Go to step  25 . If voltage is 4.65 volts or less, remove jumper wire. Go to next step.

  14. Check VREF & SIG RTN Circuits To TP Sensor

    With KOEO, measure voltage between VREF circuit (Brown/White wire) and SIG RTN circuit (Gray/Red wire) at TP sensor harness connector. See Fig 1 . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, restore all electrical connections. Go to VEHICLE REFERENCE VOLTAGE  under SYSTEM TESTS.

  15. Check For Open TP Circuit Between PCM & TP Sensor

    Turn ignition off. Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance of TP circuit (Gray/White wire) between breakout box terminal No. 89 and TP sensor harness connector. See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. See WIRING DIAGRAMS article. Go to step  25 .

  16. Check TP Circuit For Shorts To SIG RTN Or PWR GND In Harness

    Turn ignition off. Disconnect scan tool. Measure resistance between breakout box terminal No. 89 (TP circuit) and breakout box terminals No. 51 and 103 (PWR GND circuit). Record reading. Measure resistance between breakout box terminals No. 89 (TP circuit) and 91 (SIG RTN circuit). Record reading. If either resistance measurement is more than 10,000 ohms, replace faulty PCM. Go to step  25 . If either resistance measurement is 10,000 ohms or less, repair short circuit in harness. See WIRING DIAGRAMS article. Go to step  25 .

  17. DTC P1121: TP Sensor & MAF Sensor Rationality Check

    Attempt to start engine. If engine runs, go to next step. If engine does not run, check for major leaks and cracks between MAF sensor and throttle body. Repair as necessary. If no discrepancies are found, go to NO START  under SYSTEM TESTS.

  18. Check Mechanical Operation Of TP Sensor

    With KOEO, access TP V PID. Slowly open throttle from closed throttle position to wide open throttle position. While observing TP V PID, slowly open throttle. If voltage changed between 0.49-4.65 volts, go to next step. If voltage does not change between 0.49-4.65 volts, replace faulty TP sensor. Go to step  25 .

  19. Check TP Sensor Signal High Vs. Engine Load While Driving

    Drive vehicle exercising throttle. Observe TP V PID and LOAD PID. Record readings. If TP V PID is not more than 2.44 volts and LOAD PID is not less than 30 percent, go to next step. If TP V PID is more than 2.44 volts and LOAD PID is less than 30 percent, check for air leaks between MAF sensor and throttle body while engine is running. If air leaks are present, repair as necessary. If air leaks are not present, replace faulty TP sensor. Go to step  25 .

  20. Check TP Sensor Signal Low Vs. Engine Load While Driving

    Drive vehicle exercising throttle. Observe TP V PID and LOAD PID. Record readings. If TP V PID is not less than 0.24 volt and LOAD PID is not more than 55 percent, fault is unable to be duplicated at this time. Go to step  25 . If TP V PID is less than 0.24 volt and LOAD PID is more than 55 percent, verify TP sensor is securely attached to throttle body. Repair as necessary. If Continuous Memory DTC P1121 is not set, replace faulty MAF sensor. Go to step  25 .

  21. Check For TP Circuit Intermittent Voltage Input

    Start engine and idle. Run throttle up to 1500 RPM for 5 seconds. Access TP V PID. Observe TP V PID while lightly tapping on TP sensor and wiggling harness to simulate road shock. If voltage did not change to less than a minimum of 0.49 volt or more than a maximum of 4.65 volts, go to next step. If voltage changed to less than a minimum of 0.49 volt or more than a maximum of 4.65 volts, inspect TP sensor connector. If connector is okay, replace faulty TP sensor. Go to step  25 .

  22. Check TP Sensor Harness For Intermittent Opens & Shorts

    Access and observe TP V PID. With KOEO, grasp harness nearest to TP sensor connector. Shake and bend a small section of wiring harness following harness to dash panel. Shake and bend harness from dash panel to PCM. If voltage did not change to less than a minimum of 0.49 volt or more than a maximum of 4.65 volts, fault is unable to be duplicated at this time. Go to step  25 . If voltage changed to less than a minimum of 0.49 volt or more than a maximum of 4.65 volts, isolate fault in harness and repair as necessary. See WIRING DIAGRAMS article. Go to step  25 .

  23. Attempt To Re-Create DTC Or Driveability Symptom

    If KOER self-test terminates when placing transmission in Drive or Reverse, go to step  24 . Attempt to drive vehicle while still in KOER self-test. Turn ignition off. Wait 15 seconds. Start engine again. Activate KOER self-test. If DTC P0121 is still set or if KOER self-test fails to terminate, go to next step. If DTC P0121 is not set or if KOER self-test terminates, verify symptom is no longer present. Go to step  25 .

  24. Check TP Or SIG RTN Circuits For Open In Harness

    Turn ignition off. Disconnect PCM connector and TP sensor connector. Install breakout box, leaving PCM disconnected. Measure resistance of TP circuit (Gray/White wire) between breakout box terminal No. 89 and TP sensor harness connector. Record reading. Measure resistance of SIG RTN circuit (Gray/Red wire) between breakout box terminal No. 91 and TP sensor harness connector. See Fig 1 . Record reading. If either resistance measurement is less than 5 ohms, replace faulty TP sensor. Go to step  25 . If either resistance measurement is 5 ohms or more, repair open circuit. See WIRING DIAGRAMS article. Go to step  25 .

  25. Verify Trouble Shooting Of DTCs Completed

    Make sure all electrical connectors are reconnected. Clear DTCs from PCM memory using scan tool. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If the same DTC is present, replace faulty PCM. Repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are present, test is complete.
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