P0717-INPUT SPEED SENSOR 1 CIRCUIT NO SIGNAL
For a complete wiring diagram Refer to Section 8W
Theory of Operation
The Input Speed Sensor 1 (N2) is one of two hall effect speed sensors that are used by the Transmission Control Module (TCM) to calculate the transmissions turbine speed. Since the turbine speed could not be measured directly, two of the drive elements are measured. Two input speed sensors are required because both elements are not active in all gears.
- When Monitored:
Engine speed greater than 450 RPM with none of the following DTCs present: engine speed, TCM undervoltage, output speed sensor, and/or rear wheel speed DTCs. Also required are all wheel speeds above 250 RPM and no wheel slip detected (signal from the ABS system).
- Set Condition:
If the Input Speed Sensor 1 (N2) signal is equal to 0 RPM.
| Possible Causes |
| (T72) SENSOR SUPPLY VOLTAGE CIRCUIT OPEN |
| (T70) INPUT SPEED SENSOR 1 (N2) SIGNAL CIRCUIT OPEN |
| (T70) SPEED SENSOR 1 (N2) SIGNAL CIRCUIT SHORT TO ANOTHER CIRCUIT |
| (T13) SENSOR GROUND CIRCUIT OPEN |
| (T13) SENSOR GROUND CIRCUIT SHORT TO ANOTHER CIRCUIT |
| (T70) SPEED SENSOR 1 (N2) SIGNAL CIRCUIT SHORT TO GROUND |
| (T13) SENSOR GROUND CIRCUIT SHORT TO GROUND |
| SPEED SENSOR 1 (N2) |
| TRANSMISSION CONTROL MODULE |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
Diagnostic Test
1. CHECK IF DTC IS CURRENTNOTE: The Transmission Control Module stores under Environmental Data the transmission operating conditions when the DTC was set. Before erasure of any DTC, record all information pertaining to the DTC, even if there is more than one DTC stored.
With the scan tool, erase transmission DTCs.
Using the Environmental Data previously recorded, drive the vehicle and try to duplicate the conditions in which the DTC originally set.
Does the DTC reset?
Yes
- Go To 2
No
- Go To 10
2. CHECK THE (T72) SENSOR SUPPLY VOLTAGE CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Disconnect the Electrohydraulic Control Unit Assembly harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance of the (T72) Sensor Supply Voltage circuit from the TCM C2 harness connector to the Electrohydraulic Control Unit Assembly harness connector.
Is the resistance above 5.0 ohms?
Yes
- Repair the (T72) Sensor Supply Voltage circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 3
3. CHECK THE (T70) INPUT SPEED SENSOR 1 (N2) SIGNAL CIRCUIT FOR AN OPEN
Measure the resistance of the (T70) Input Speed Sensor 1 (N2) Signal circuit from the TCM C2 harness connector to the Electrohydraulic Control Unit Assembly harness connector.
Is the resistance above 5.0 ohms?
Yes
- Repair the (T70) Input Speed Sensor 1 (N2) Signal circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 4
4. CHECK THE (T13) SENSOR GROUND CIRCUIT FOR AN OPEN
Measure the resistance of the (T13) Sensor Ground circuit from the TCM C2 harness connector to the Electrohydraulic Control Unit Assembly harness connector.
Is the resistance above 5.0 ohms?
Yes
- Repair the (T13) Sensor Ground circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 5
5. CHECK THE (T70) INPUT SPEED SENSOR 1 (N2) SIGNAL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT(S)
Measure the resistance of the (T70) Input Speed Sensor 1 (N2) Signal circuit to all the other circuits in the Electrohydraulic Control Unit Assembly harness connector.
Is the resistance below 5.0 ohms between the (T70) Input Speed Sensor 1 (N2) Signal circuit and any other circuit(s) in the Electrohydraulic Control Unit Assembly harness connector?
Yes
- Repair the (T70) Input Speed Sensor 1 (N2) Signal circuit for a short to another circuit(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 6
6. CHECK THE (T70) INPUT SPEED SENSOR 1 (N2) SIGNAL CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T70) Input Speed Sensor 1 (N2) Signal circuit.
Is the resistance below 5.0 ohms?
Yes
- Repair the (T70) Input Speed Sensor 1 (N2) Signal circuit for a short to ground.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 7
7. CHECK THE (T13) SENSOR GROUND CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT(S)
Measure the resistance between the (T13) Sensor Ground circuit to all the other circuits in the Electrohydraulic Control Unit Assembly harness connector.
Is the resistance below 5.0 ohms between the (T13) Sensor Ground circuit and any other circuit(s) in the Electrohydraulic Control Unit Assembly harness connector.
Yes
- Repair the (T13) Sensor Ground circuit for a short to another circuit(s)
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 8
8. CHECK THE (T13) SENSOR GROUND CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T13) Sensor Ground circuit.
Is the resistance below 5.0 ohms?
Yes
- Repair the (T13) Sensor Ground circuit for a short to ground.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Go To 9
9. CHECK THE INPUT SPEED SENSOR 1 (N2) SIGNAL
Reconnect the Electrohydraulic Control Unit Assembly harness connector.
Using a Lab Scope, backprobe the (T70) Input Speed Sensor 1 (N2) Signal circuit at the TCM C2 harness connector.
WARNING: Properly support the vehicle.
Raise all drive wheels off the ground.
Start the engine.
WARNING: To avoid personal injury or death, keep hands and feet clear of rotating wheels.
Place gear selector in drive and increase vehicle speed to engage 2nd gear.
Compare the scope pattern on the Lab Scope with a typical 5-volt square wave pattern.
Is the scope pattern comparable to the typical 5-volt square wave signal scope pattern?
Yes
- Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM per the Service Information. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE - REMOVAL)
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Replace the Input Speed Sensor 1 (N2) per the Service Information.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
10. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
No
- Test Complete.