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Home >> Honda >> 2021 >> Insight EX >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTC Diagnostics (1 Of 4) >> DTC Troubleshooting >> DTC P0121
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DTC P0121

DTC P0121  : TP Sensor A Out of Range

Do not insert your fingers into the installed throttle body when you turn the vehicle to the ON mode, or while the vehicle is in ON mode. If you do, you will seriously injure your fingers if the throttle valve is activated.
NOTE: Before you troubleshoot, review the general troubleshooting information .
DTC Description Confirmed DTC Pending DTC
P0121 TP Sensor A Out of Range    

DTC (PGM-FI)

  1. Problem verification 1

    -1. Turn the vehicle to the ON mode.

    -2. Clear the DTC with the HDS.

    -3. Check the parameter(s) below with the HDS.

    Signal Threshold Current conditions
    Values Unit Values Unit
    TP Sensor A Less than 0.37 V    

    Data List

    Do the current condition(s) match the threshold?

    YES 

    The failure is duplicated. Go to step 3.

    NO 

    Go to step 2.

  2. Problem verification 2

    -1. Check the parameter(s) below with the HDS.

    Signal Threshold Current conditions
    Values Unit Values Unit
    TP Sensor A More than 4.48 V    

    Data List

    Do the current condition(s) match the threshold?

    YES 

    The failure is duplicated. Go to step 7.

    NO 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the throttle body and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot .

  3. Determine possible failure area (THL1 line, others)

    -1. Check for Pending or Confirmed DTCs with the HDS.

    DTC Description Confirmed DTC Pending DTC
    P0121 TP Sensor A Out of Range    
    P0221 TP Sensor B Out of Range    

    DTC (PGM-FI)

    Are DTC P0121 and P0221 indicated at the same time?

    YES 

    Go to step 5.

    NO 

    Go to step 4.

  4. Shorted wire check (THL1 line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connectors.

    PCM connector E (80P)
    Throttle body 6P connector

    -4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector E (80P): disconnected
      Throttle body 6P connector: disconnected
    Test point 1 Throttle body 6P connector (female terminals) No. 6:
    Test point 2 Body ground
    GHH384833Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the THL1 wire between the PCM (E50) and the throttle body.

    NO 

    The THL1 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM .

  5. Determine possible failure area (throttle body, others)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    Throttle body 6P connector

    -3. Turn the vehicle to the ON mode.

    -4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
      Throttle body 6P connector: disconnected
    Test point 1 Throttle body 6P connector (female terminals) No. 5:
    Test point 2 Body ground
    GHH384835Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V?

    YES 

    Replace the throttle body .

    NO 

    Go to step 6.

  6. Open wire check (VCC3 line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connector.

    PCM connector E (80P)

    -4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      Throttle body 6P connector: disconnected
      PCM connector E (80P): disconnected
    Test point 1 Throttle body 6P connector (female terminals) No. 5:
    Test point 2 PCM connector E (80P) No. 75
    GHH384837Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The VCC3 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM .

    NO 

    Repair an open in the VCC3 wire between the PCM (E75) and the throttle body.

  7. Determine possible failure area (SG3 line, others)

    -1. Check for Pending or Confirmed DTCs with the HDS.

    DTC Description Confirmed DTC Pending DTC
    P0121 TP Sensor A Out of Range    
    P0221 TP Sensor B Out of Range    

    DTC (PGM-FI)

    Are DTC P0121 and P0221 indicated at the same time?

    YES 

    Go to step 10.

    NO 

    Go to step 8.

  8. Determine possible failure area (throttle body, others)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    Throttle body 6P connector

    -3. Turn the vehicle to the ON mode.

    -4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
      Throttle body 6P connector: disconnected
    Test point 1 Throttle body 6P connector (female terminals) No. 6:
    Test point 2 Body ground
    GHH384839Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V?

    YES 

    Replace the throttle body .

    NO 

    Go to step 9.

  9. Open wire check (THL1 line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connector.

    PCM connector E (80P)

    -4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      Throttle body 6P connector: disconnected
      PCM connector E (80P): disconnected
    Test point 1 Throttle body 6P connector (female terminals) No. 6:
    Test point 2 PCM connector E (80P) No. 50
    GHH384841Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The THL1 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM .

    NO 

    Repair an open in the THL1 wire between the PCM (E50) and the throttle body.

  10. Open wire check (SG3 line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connectors.

    PCM connector E (80P)
    Throttle body 6P connector

    -4. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector E (80P): disconnected
      Throttle body 6P connector: disconnected
    Test point 1 Throttle body 6P connector (female terminals) No. 3:
    Test point 2 PCM connector E (80P) No. 76
    GHH384843Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The SG3 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM .

    NO 

    Repair an open in the SG3 wire between the PCM (E76) and the throttle body.

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