P0716 Input/Turbine speed sensor circuit Range/Performance has shown up three times on my 2011 GS A6. Each time I was stopped at a light when there was a clunk in the rear end/transmission and then the check engine light came on. When I drove away from the light the car was in limp mode, would not drive over 29 mph and stayed in second gear. The first two time I limped it home but the next day I started it up and it drove perfectly. The third time I limped it home and started it up one hour later and it drove perfect. Each of these is about a month and maybe 2000 miles apart. My research on the threads here would indicate that it’s probably either the input speed sensor in the trans. or somewhere in the wiring between the computer and the transmission. My biggest concern is that if I take it in to a shop it will be running perfectly at the time and it’s difficult to troubleshoot something that’s working properly. I hate to have them start throwing parts at it but in all of the cases that I’ve read about it has never stayed in limp mode for anyone past the next restart. Ideas?

 

My shop manual only goes back to 2009, but this info is probably still relevant. Could be a connection issue as it does mention a couple of time..........visually inspect the ISS, harness, connector, the control solenoid (w/body and TCM) valve assembly pins for metallic debris

DTC P0716

Circuit/System Description
The automatic transmission (AT) input and output speed sensor (ISS and OSS) assembly each are part of a single harness. The ISS is a hall-effect type sensor. The sensors mount to the control valve upper body assembly. The assembly connects to the control solenoid (w/body and TCM) valve assembly through a 3-wire harness and connector. The sensor end faces the 1-2-3-4 and 3-5-R clutch housing machined teeth surface. The sensor receives 8.3-9.3 volts on the input/output speed sensor (ISS/OSS) Supply Voltage circuit from the transmission control module (TCM). As the 1-2-3-4 and 3-5-R clutch housing rotates, the sensor produces a signal frequency based on the machined surface of the clutch housing. This signal is transmitted through the ISS signal circuit to the control solenoid (w/body and TCM) valve assembly. The control solenoid (w/body and TCM) valve assembly uses the ISS signal to determine line pressure, transmission shift patterns, torque converter clutch (TCC) slip speed and gear ratio.

Conditions for Setting the DTC
P0716
• The TCM detects an unrealistic drop in input shaft speed.

• ISS DTC P0716 is not failed this ignition.

• Transmission input speed is 686 RPM or greater for 2 seconds.

• Transmission input speed drops 653 RPM and does not recover within 0.80 seconds.

Action Taken When the DTC Sets
• P0716 and P0717 are Type A DTCs.

• The TCM freezes transmission adaptive functions.

• The TCM turns OFF all solenoids.

• The TCM inhibits TU/TD functions.

Diagnostic Aids
Inspect the ISS, harness, connector, and control solenoid (w/body and TCM) valve assembly pins for metallic debris and the 1-2-3-4 and 3-5-R clutch housing machined teeth surface for damage or misalignment. Proper torque of the OSS mounting bolt is critical to proper OSS operation. Use the terminal test kit for any test that requires probing the control solenoid (w/body and TCM) valve assembly harness connector or a component harness connector.

Circuit/System Testing
1) With the ignition ON, observe the transmission ISS/OSS supply voltage circuit status on the scan tool, the parameter should display OK. The ISS supply voltage should be 8.3-9.3 volts.
⇒ If the circuit status does not display OK, disconnect the ISS/OSS connector from the control solenoid (w/body and TCM) valve assembly and recheck the scan tool display.

⇒ If the transmission ISS/OSS supply voltage circuit status still displays OK, visually inspect the ISS, harness, connector, the control solenoid (w/body and TCM) valve assembly pins for metallic debris and 1-2-3-4 and 3-5-R clutch housing machined teeth surface for damage or misalignment. Repair or replace any damaged components.

2) Perform the Control Solenoid Valve and Transmission Control Module Assembly Input Shaft Speed/Output Shaft Speed Input Test. The scan tool should display Transmission ISS between 100-400 RPM.
⇒ If 100-400 ISS RPM is displayed, replace the ISS/OSS assembly.

⇒ If no ISS RPM is displayed or the RPM is out of range, replace the control solenoid (w/body and TCM) valve assembly.

 

I guess my biggest question is when it gets a faulty signal and goes into limp mode it only does it briefly. If I shut off the car and restart it, it drives fine and the problem seems to be gone. I assume if I take it to a shop and it has reset and it is driving normally will there anything for the shop to find? Won’t all of the testing listed above show normal if the problem is not currently there?