DTC Troubleshooting: P0718
DTC P0718: Input Shaft (Mainshaft) Speed Sensor (Intermittent Failure)
NOTE:
Before you troubleshoot, review the General Troubleshooting Information.
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0718 Input Shaft (Mainshaft) Speed Sensor (Intermittent Failure)
      

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Raise the vehicle on a lift. Make sure it is securely supported, and allow all four wheels to rotate freely.

?4.
Start the engine.

?5.
Disable the VSA by pressing the VSA OFF button.

NOTE: Enter the VSA maintenance mode in case of the vehicle speed above 31 mph (50 km/h).

?6.
Test-drive the vehicle in D position/mode, and keep the vehicle at speeds over 12 mph (20 km/h). Compare the Input Shaft (Mainshaft) Speed (rpm) and the Output Shaft (Countershaft) Speed (rpm) with the HDS. Slow down, and stop the wheels.
Signal
Current conditions
Values
Unit
Input Shaft (Mainshaft) Speed (rpm)
    
Output Shaft (CounterShaft) Speed (rpm)
    

Are the speeds about the same?

     
YES
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals between the input shaft (mainshaft) 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
     
     
     
The failure is duplicated. Go to step 2.
2.
Open wire check (VCC2 line):

Open wire check (VCC2 line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.

?3.
Turn the vehicle to the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
 
Input shaft (mainshaft) speed sensor 3P connector: disconnected
Test circuit
VCC2
Test point 1
Input shaft (mainshaft) speed sensor 3P connector No. 3 (GRN)
Test point 2
Body ground


Is there about 5 V?

     
YES
     
     
     
The VCC2 wire is OK. Go to step 3.
     
NO
     
     
     
Repair an open in the VCC2 wire between the input shaft (mainshaft) speed sensor and the PCM.?
3.
Determine possible failure area (NM line, others):

Determine possible failure area (NM line, others)
?1.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
 
Input shaft (mainshaft) speed sensor 3P connector: disconnected
Test circuit
NM
Test point 1
Input shaft (mainshaft) speed sensor 3P connector No. 2 (RED)
Test point 2
Body ground


Is there about 5 V?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Go to step 5.
4.
Open wire check (SG2 line):

Open wire check (SG2 line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Input shaft (mainshaft) speed sensor 3P connector: disconnected
Test circuit
SG2
Test point 1
Input shaft (mainshaft) speed sensor 3P connector No. 1 (GRY)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
     
NO
     
     
     
Repair an open in the SG2 wire between the input shaft (mainshaft) speed sensor and the PCM.?
5.
Shorted wire check (NM line):

Shorted wire check (NM line)
?1.
Turn the vehicle to the OFF (LOCK) 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
Vehicle OFF (LOCK) mode
 
Input shaft (mainshaft) speed sensor 3P connector: disconnected
 
PCM connector B (51P): disconnected
Test circuit
NM
Test point 1
Input shaft (mainshaft) speed sensor 3P connector No. 2 (RED)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the NM wire between the input shaft (mainshaft) speed sensor and the PCM.?
     
NO
     
     
     
The NM wire is not shorted. Repair an open in the NM wire between the input shaft (mainshaft) speed sensor and the PCM.?