DTC Troubleshooting: P0720
DTC P0720: Output Shaft (Countershaft) Speed Sensor Circuit Malfunction
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0720 Output Shaft (Countershaft) Speed Sensor Circuit Malfunction
      

1.
Problem verification:

Problem verification
?1.
Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.

?2.
Test-drive under these conditions:
Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
Transmission in 4th
Engine speed between 2,000?3,000 rpm
Drive for several minutes, then decelerate (with throttle fully closed) for 8 seconds

?3.
Check the C SHAFT SPD in the DATA LIST 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.?
     
NO
     
     
     
Go to step 2.
2.
Determine possible failure area (VCC1 line, SG1 line, others):

Determine possible failure area (VCC1 line, SG1 line, others)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Press the engine start/stop button to select the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
 
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test circuit
VCC1, SG1
Test point 1
Output shaft (countershaft) speed sensor 3P connector No. 1 (BLU)
Test point 2
Output shaft (countershaft) speed sensor 3P connector No. 3 (PNK)


Is there about 5.0 V?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Go to step 3.
3.
Open wire check (VCC1 line):

Open wire check (VCC1 line)
?1.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
 
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test circuit
VCC1
Test point 1
Output shaft (countershaft) speed sensor 3P connector No. 3 (PNK)
Test point 2
Body ground


Is there about 5.0 V?

     
YES
     
     
     
The VCC1 wire is OK. Repair an open in the SG1 wire between the PCM (C33) and the output shaft (countershaft) speed sensor, then do the repair verification.
     
NO
     
     
     
Repair an open in the VCC1 wire between the PCM (C32) and the output shaft (countershaft) speed sensor, then do the repair verification.
4.
Determine possible failure area (Output shaft (countershaft) speed sensor, NC line):

Determine possible failure area (Output shaft (countershaft) speed sensor, NC line)
?1.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
 
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test circuit
NC
Test point 1
Output shaft (countershaft) speed sensor 3P connector No. 2 (TAN)
Test point 2
Body ground


Is there about 5.0 ?

     
YES
     
     
     
     
NO
     
     
     
Go to step 5.
5.
Shorted wire check (NC line):

Shorted wire check (NC line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Jump the SCS line with the HDS


?3.
Disconnect the following connector.

?4.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
PCM connector C (51P): disconnected
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test circuit
NC
Test point 1
PCM connector C (51P) No. 21 (TAN)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the NC wire between the PCM (C21) and the output shaft (countershaft) speed sensor, then do the repair verification.
     
NO
     
     
     
The NC wire is not shorted. Go to step 6.
6.
Open wire check (NC line):

Open wire check (NC line)
?1.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
PCM connector C (51P): disconnected
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test circuit
NC
Test point 1
PCM connector C (51P) No. 21 (TAN)
Test point 2
Output shaft (countershaft) speed sensor 3P connector No. 2 (TAN)


Is there continuity?

     
YES
     
     
     
The NC wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then do the repair verification.?
     
NO
     
     
     
Repair an open in the NC wire between the PCM (C21) and the output shaft (countershaft) speed sensor, then do the repair verification.
Repair verification (OBD STATUS check):

?1.
Reconnect all connectors.

?2.
Exit the SCS mode with the HDS.


?3.
Press the engine start/stop button to select the ON mode.

?4.
Reset the PCM with the HDS.


?5.
Do the PCM idle learn procedure.

?6.
Test-drive under these conditions:
Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
Transmission in 4th
Engine speed between 2,000?3,000 rpm
Drive for several minutes, then decelerate (with throttle fully closed) for 8 seconds

?7.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0720 Output Shaft (Countershaft) Speed Sensor Circuit Malfunction
      


Is DTC P0720 indicated?

     
YES
     
     
     
Check for poor connections or loose terminals at the output shaft (countershaft) speed sensor and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.
     
NO
     
     
     
Troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.?