N3 Input Speed Sensor Circuit

P0715 - N3 INPUT SPEED SENSOR CIRCUIT





When Monitored and Set Condition

- When Monitored: Engine speed greater than 450 RPM, no engine speed DTCs, no TCM undervoltage system operation, no output speed sensor DTCs (signal from the ABS system), all wheel speeds above 250 RPM (signal from the ABS system), no rear wheel speed DTCs (signal from the ABS system), and no wheel slip detected (signal from the ABS system), no shifting operation, detected gear is 3rd or 4th and the detected gear is the actual vehicle gear.
- Set Condition: If the N3 input speed sensor signal is equal to 0 RPM, short signal circuit to ground, shorted to battery, an open input speed sensor, a faulty input speed sensor, or an open sensor supply circuit.






Diagnostic Test


1. PRE-DIAGNOSTIC CHECK OUT





NOTE: Low fluid level can be the cause of many transmission problems. If the fluid level is low, locate and repair the leak then check and adjust the fluid level.

NOTE: Always perform diagnostics with a fully charged battery to avoid false symptoms.

With the DRB III(R), read Engine DTCs. Check and repair all engine DTCs prior to performing transmission symptom diagnostics.

With the DRB III(R), read and record all Transmission DTCs.


NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.

Most DTCs set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run.


NOTE: Check for any Technical Service Bulletins that may apply.

Perform this procedure prior to Symptom diagnosis.

Continue

Go To 2



2. CHECK FOR CURRENT DTC






NOTE: If the TCM detects and stores a DTC, the TCM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the DRB III(R) at the same time the DTC is displayed.


NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

Turn the ignition on.

With the DRB III(R), erase Transmission DTCs.


NOTE: It maybe necessary to road test the vehicle for this DTC to set.

With the DRB III(R), read Transmission DTCs.

Did this DTC set again?

Yes

- Go To 3

No

- Go To 11




3. SENSOR SUPPLY VOLTAGE CIRCUIT OPEN





Turn the ignition off.

Disconnect the TCM C2 harness connector.

Disconnect the Transmission Solenoid Assembly harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the Sensor Supply Voltage circuit from the TCM C2 harness connector to the Transmission Solenoid Assembly harness connector.

Is the resistance below 5.0 ohms?

Yes

Go To 4

No

- Repair the Sensor Supply Voltage circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



4. N3 INPUT SPEED SENSOR SIGNAL CIRCUIT OPEN





With the ignition off.

Measure the resistance of the N3 Input Speed Sensor Signal circuit from the TCM C2 harness connector to the Transmission Solenoid Assembly harness connector.

Is the resistance below 5.0 ohms?

Yes

Go To 5

No

- Repair the N3 Input Speed Sensor Signal circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



5. SENSOR GROUND CIRCUIT OPEN





With the ignition off.

Measure the resistance of the Sensor Ground circuit from the TCM C2 harness connector to the Transmission Solenoid Assembly harness connector.

Is the resistance below 5.0 ohms?

Yes

Go To 6

No

- Repair the Sensor Ground circuit for an open.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



6. N3 SPEED SENSOR SIGNAL CIRCUIT SHORT TO OTHER CIRCUITS





With the ignition off.

Measure the resistance from the N3 Speed Sensor Signal circuit to all other circuits in the Transmission Solenoid Assembly harness connector.

Is the resistance above 100 kohms for all measurements?

Yes

- Go To 7

No

- Repair the N3 Speed Sensor Signal circuit for a short to other circuit(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



7. N3 INPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND





With the ignition off.

Measure the resistance between ground and the N3 Input Speed Sensor Signal circuit.

Is the resistance above 100 kohms?

Yes

- Go To 8

No

- Repair the N3 Input Speed Sensor Signal circuit for a short to ground.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



8. SENSOR GROUND CIRCUIT SHORT TO OTHER CIRCUITS





With the ignition off.

Measure the resistance from the Sensor Ground circuit to all other circuits in the Transmission Solenoid harness connector.

Is the resistance above 100 kohms for all measurements?

Yes

- Go To 9

No

- Repair the Sensor Ground circuit for a short to other circuits.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



9. SENSOR GROUND CIRCUIT SHORT TO GROUND





With the ignition off.

Measure the resistance between ground and the Sensor Ground circuit.

Is the resistance above 100 kohms?

Yes

- Go To 10

No

- Repair the Sensor Ground circuit for a short to ground.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



10. CHECKING N3 INPUT SPEED SENSOR W/ LAB SCOPE





With the ignition off.

Reconnect the TCM C2 harness connector.

Reconnect the Transmission Solenoid Assembly harness connector.

Turn the ignition on.

With the DRB III(R)/PEP Module being used as a Dual Channel Lab Scope with Miller special tool #6801, backprobe N3 Input Speed Sensor Signal circuit using Channel 1 at the TCM C2 harness connector.




WARNING: PROPERLY SUPPORT THE VEHICLE.

Raise all drive wheels off the ground.

Start the engine.


WARNING: BE SURE TO 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 DRB III(R) with a typical 5 volt square wave pattern.

Does the scope pattern match a typical 5 volt square wave signal scope pattern?

Yes

- Replace the Transmission Control Module.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test

No

- Replace the N3 Input Speed Sensor.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test



11. INTERMITTENT WIRING AND CONNECTORS

The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.

Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.

Wiggle the wires while checking for shorts and open circuits.


NOTE: Check for any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test

No

- Test Complete.