Diesel Data: Automotive Repair

P0716












Circuit Description

The Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) is a permanent magnet with a coil of wire wound around it. The A/T ISS mounts in the transmission case facing the drive sprocket of the input shaft. An air gap of 1.14-2.77 mm (0.045-0.109 in) between the sensor and drive sprocket must be maintained in order to transmit an accurate AC voltage. Sensor voltage varies from 0.5 volts AC at 100 RPM to more than 100 volts at 8000 RPM. This diagnostic monitors the A/T ISS circuit. The circuit may be functional but not in the normal operating range. This diagnostic indicates stuck, erratic, or intermittent values, indicating poor performance of the system. The A/T ISS has a resistance value of 1300-1950 ohms.

When the PCM detects an unrealistically large change in data from the A/T Input (Shaft) Speed Sensor, then DTC P0716 sets. DTC P0716 is a Type A DTC.

Conditions for Setting the DTC

^ No TP DTCs P0121, P0122 or P0123 are set.

^ No Vehicle Speed Sensor (VSS) DTCs P0502 or P0503 are set.

^ No A/T ISS DTC P0717 is set.

^ No 1-2 shift solenoid valve electrical DTC P0753 is set.

^ No 2-3 shift solenoid valve electrical DTC P0758 is set.

^ No 1-2 shift solenoid valve performance DTC P0751 is set.

^ No 2-3 shift solenoid valve performance DTC P0756 is set.

^ The vehicle speed is greater than 11 km/h (7 mph).

^ The throttle angle is greater than 12.8.

^ The engine running for more than 5 seconds.

^ Not in fuel shut off

^ Changes to the input speed by 1000 RPM or greater in 0.075 seconds 10 times in 10 seconds


Action Taken When the DTC Sets

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ SERVICE ENGINE SOON displays on the Driver Information Center (DIC).

^ The PCM commands default line pressure,

^ The PCM inhibits Torque Converter Clutch

^ The PCM disables steady state adapts.

^ The PCM disables upshift adapts.

^ The PCM disables garage shift adapts.

^ The PCM calculates input speed from vehicle speed and commanded gear.

Conditions for Clearing the MIL/DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.


Diagnostic Aids

^ Ensure the engine wiring harness is not located near spark plug wires or DIS coils.

^ Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. inspect the wiring for poor electrical connections at the A/T ISS 2-way connector. Look for the following conditions:

- A bent terminal

- A backed out terminal

- A damaged terminal

- Poor terminal tension

- A chafed wire

^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.


Test Description

The numbers below refer to the step numbers on the diagnostic chart.

1. This Step ensures that you perform the Powertrain On-Board Diagnostic System Check.

2. This Step verifies that the DTC is set and the scan tool displays the Automatic Transmission Input (Shaft) Speed sensor RPM.

3. This Step inspects circuit 1230 and circuit 1231 for an AC voltage. Use the J 35616 Test Connector Adapter Kit, so as not to damage the terminals.

4. This Step inspects circuit 1230 for a voltage of 300 mV or greater.

5. This Step inspects circuit 1230 for an open or a short to ground, if the voltmeter displays less than 300 mV.

6. This Step verifies that circuit 1231 is not open.

7. This Step inspects circuit 1231 for an open, if the voltmeter displays less than 300 mV.

8. This Step measures the resistance value of the Automatic Transmission Input (Shaft) Speed sensor and circuitry. The ohmmeter must display a value between 1300-1950 ohms. Use the J 35616 Test Connector Adapter Kit, so as not to damage the terminals.

10. This Step inspects circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for an open, if the resistance value is greater than 1950 ohms. You must replace the transmission harness if you find an open in the harness.

12. This Step inspects circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for a short together, if the resistance is less than 1300 ohms. You must replace the transmission harness if you find a short together in the harness.

13. This Step tests circuit 1230 and circuit 1231 for a short to ground, if the resistance is less than 100 ohms. You must replace the transmission harness if you find a short to ground in the harness.

15. This Step replaces the A/T ISS Sensor after you verify that the Engine Wiring Harness and the Automatic Transmission Wiring Harness are functioning normally.

16. This Step replaces the PCM after you have inspected the components and circuitry.