RPM Signal From ECM - Not Present

P0727

Rpm signal from ECM - Not present

Function
The rpm signal is calculated by the ECM and transferred to the Tiptronic control module via a data lead (CAN bus). The rpm signal is required in order to determine the gear required in each case and, if necessary, to initiate shifting operations.

The "restricted driving program" is activated in the event of a faulty signal.

Diagnosis conditions
- Selector lever position "D"
- Transmission output speed [>] 192 rpm

P0727:

Wiring diagram







Diagnosis procedure

NOTE: The rpm signal can be tested with the Porsche System Tester 2 (actual value/speed).







1 Check data lead from Tiptronic control module to ECM control unit for continuity.

1. Pull off Tiptronic control module connector.
2. Pull off ECM connector.
3. Connect ohmmeter to Tiptronic control module connector, pin 85 (or pin 86), and ECM control unit connector, pin 85 (or pin 86).

Indication: 0...5 Ohms

If Infinity Ohm is indicated, check wiring harness for crushing and chafing damage.

1 Check data lead from Tiptronic control module to ECM control unit for short circuit to ground.

1. Connect ohmmeter to Tiptronic control module connector, pin 85 (or pin 86), and ground.

Indication: Infinity Ohm

If 0...5 Ohms is indicated, check wiring harness for crushing and chafing damage.

1 Check data lead from Tiptronic control module to ECM control unit for short circuit to plus.

1. Switch on ignition.
2. Connect voltmeter to Tiptronic control module connector, pin 85 (or pin 86), and ground.

Indication: 0 Volt

If battery voltage is indicated, check wiring harness for crushing and chafing damage.