DTC Troubleshooting: P0720
DTC P0720: Output Shaft (Countershaft) Speed Sensor Circuit Malfunction
NOTE: Before you troubleshoot, 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 several minutes.

?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. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.?
     
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.
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 No. 1
Test point 2
Output shaft (countershaft) speed sensor 3P connector No. 3


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
Vehicle ON mode
 
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test point 1
Output shaft (countershaft) speed sensor 3P connector No. 3
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 (C42) and the output shaft (countershaft) speed sensor.?
     
NO
     
     
     
Repair an open in the VCC1 wire between the PCM (C41) and the output shaft (countershaft) speed sensor.?
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
Vehicle ON mode
 
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test point 1
Output shaft (countershaft) speed sensor 3P connector No. 2
Test point 2
Body ground


Is there about 5.0 V ?

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

Shorted wire check (NC line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Jump the SCS line with the HDS


?3.
Disconnect the following connector.
PCM connector C (51P)

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
PCM connector C (51P): disconnected
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test point 1
PCM connector C (51P) No. 33
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short in the NC wire between the PCM (C33) and the output shaft (countershaft) speed sensor.?
     
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
Vehicle OFF (LOCK) mode
PCM connector C (51P): disconnected
Output shaft (countershaft) speed sensor 3P connector: disconnected
Test point 1
PCM connector C (51P) No. 33
Test point 2
Output shaft (countershaft) speed sensor 3P connector No. 2


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 recheck. If DTC P0720 goes away and the PCM was updated, troubleshooting is complete. If DTC P0720 goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Repair an open in the NC wire between the PCM (C33) and the output shaft (countershaft) speed sensor.?