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DTC P0721 (1.5 L Engine) (2020 2021)

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DTC P0721  : Output Shaft (Countershaft) Speed Sensor Out of Range

NOTE:  Before you troubleshoot, review the general troubleshooting information .

DTC Description Confirmed DTC Pending DTC
P0721 Output Shaft (Countershaft) Speed Sensor Out of Range    

DTC (PGM-FI)

  1. Problem verification

    -1. Start the engine.

    -2. Hold the engine speed at 3, 000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.

    -3. Test-drive the vehicle several minutes.

    -4. Check the parameter (s) below with the HDS.

    Signal Current conditions
    Values Unit
    C Shaft Spd    

    Is any vehicle speed indicated?

    YES 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the output shaft (countershaft) speed sensor 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 .

    NO 

    The failure is duplicated. Go to step 2.

  2. Determine possible failure area (VCC1 line or SG1 line, others)

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

    -2. Disconnect the following connector.

    Output shaft (countershaft) speed sensor 3P connector

    -3. Turn the vehicle to the ON mode.

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

    Test condition Vehicle ON mode
      Output shaft (countershaft) speed sensor 3P connector: disconnected
    Test point 1 Output shaft (countershaft) speed sensor 3P connector (female terminals) No. 1:
    Test point 2 Output shaft (countershaft) speed sensor 3P connector (female terminals) No. 3:
    GHH393480Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V?

    YES 

    Go to step 4.

    NO 

    Go to step 3.

  3. Open wire check (VCC1 line)

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

    Test condition Vehicle ON mode
      Output shaft (countershaft) speed sensor 3P connector: disconnected
    Test point 1 Output shaft (countershaft) speed sensor 3P connector (female terminals) No. 3:
    Test point 2 Body ground
    GHH393482Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V?

    YES 

    The VCC1 wire is OK. Repair an open in the SG1 wire between the PCM (E71) and the output shaft (countershaft) speed sensor.

    NO 

    Repair an open in the VCC1 wire between the PCM (E70) and the output shaft (countershaft) speed sensor.

  4. Determine possible failure area (output shaft (countershaft) speed sensor, others)

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

    Test condition Vehicle ON mode
      Output shaft (countershaft) speed sensor 3P connector: disconnected
    Test point 1 Output shaft (countershaft) speed sensor 3P connector (female terminals) No. 2:
    Test point 2 Body ground
    GHH393484Courtesy of HONDA, U.S.A., INC.

    Is there about 5.0 V ?

    YES 

    Replace the output shaft (countershaft) speed sensor .

    NO 

    Go to step 5.

  5. Shorted wire check (NC 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
    Output shaft (countershaft) speed sensor 3P connector: disconnected
    PCM connector E (80P): disconnected
    Test point 1 PCM connector E (80P) No. 66
    Test point 2 Body ground

    Is there 1 MΩ or more?

    YES 

    The NC wire is not shorted. Go to step 6.

    NO 

    Repair a short in the NC wire between the PCM (E66) and the output shaft (countershaft) speed sensor.

  6. Open wire check (NC line)

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

    Test condition Vehicle OFF (LOCK) mode
    Output shaft (countershaft) speed sensor 3P connector: disconnected
    PCM connector E (80P): disconnected
    Test point 1 Output shaft (countershaft) speed sensor 3P connector (female terminals) No. 2:
    Test point 2 PCM connector E (80P) No. 66
    GHH393486Courtesy of HONDA, U.S.A., INC.

    Is there 1.0 Ω or less?

    YES 

    The NC 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 P0721 goes away and the PCM was substituted, replace the original PCM .

    NO 

    Repair an open in the NC wire between the PCM (E66) and the output shaft (countershaft) speed sensor.