P0846
Fault code P0846Oil pressure switch 2, transmission [Transmission Fluid Pressure Sensor/Switch 'B' Circuit Range/Performance]
NOTE: The ignition must be switched off and then switched on again in order to display an error message in the instrument cluster.
Use the 'Actual values' menu in the Porsche System Tester II No. 9588 to check the transmission status and the actual values of the shift solenoid valves and sensors.
Diagnostic conditions
NOTE: The ATF fluid level in the transmission must be OK and the specified ATF fluid must be used. The ATF filter and cooler must not be blocked.
The following requirements are met for at least 0.5 seconds:
- Voltage greater than 10.2 V and less than 15.5 V
- Ignition on
- Internal Tiptronic control module function test was completed successfully
- Engine runs without malfunctions, engine speed '> 400 rpm'
- Temperature of ATF fluid >= 20 °C
The fault types 'Open circuit/Short circuit to B+' are set after the following conditions occur 12 times:
- Selector lever in position 'D', gear 1 engaged
- Oil pressure switch 2 signal is 'OFF' for more than one second
- Line pressure >= 6 bar
The fault type 'Short circuit to ground' is set after the following conditions occur 12 times:
- Selector lever position 'P, R, N'
- Oil pressure switch 2 signal is 'ON' for more than one second
Possible causes of fault
NOTE:
The 'Diagnosis/troubleshooting' shown below is adapted to suit the fault type displayed in the tester (please note fault type numbering 1, 2,... etc..). The fault memory Info key [F8] on the Porsche System Tester II No. 9588 can be used to read out the fault type in the 'extended fault memory'.
- 1. 'Open circuit/short circuit to B+': No signal from oil pressure switch 2
- 2. 'Short circuit to ground': Continuous signal from oil pressure switch 2
Affected pins
Tiptronic control module plug:
- Pin 25 'transmission oil pressure switch 2', existing transmission wiring plug 'pin B8'
Diagnosis/troubleshooting G 0210
Wiring diagram of transmission oil pressure switch 2
1 - Tiptronic control module
2 - Oil pressure switch 1, transmission
3 - Oil pressure switch 2, transmission
24 - Pin (24)
25 - Pin (25)
I1 - Current flow for oil pressure switch 1
I2 - Current flow for oil pressure switch 2
VIG - Operating voltage
Data on transmission oil pressure switch 2
- Max. power consumption: 10 mA at an operating voltage (VIG) of 16.5 V
NOTE:
Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' on the Tiptronic control module plug connection and the 'pins' on the 'existing transmission wiring' plug connection are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.
NOTE:
Replacing control module: Before replacing the 'Tiptronic control module', the ground connections, power supply and plug connections on the control module must be checked. Please observe the coding of the control module. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the 'Tiptronic control module' should be detected and remedied.
Danger:
Danger of burns from hot ATF fluid.
Skin or clothing may burn following contact with hot ATF fluid.
- Always allow ATF fluid to cool before draining.
- Wear suitable protective clothing.
- Use a suitable collecting container.
1. Troubleshooting only for fault type: 'Open circuit/short circuit to B+'
2. Troubleshooting only for fault type: 'Short circuit to ground'
