A/T, Cooling System - MIL ON/DTC's P2181/P3081 Set
911 (997)2/05
Section 1, Engine
5/9/05
Check Engine Light Activated - Diagnostic Code P2181 and/or P3081 in the DME Fault Memory
Vehicle Type:
911 Carrera (997)
Model Year:
2005
Equipment: Tiptronic Transmission (I No. 249)
Concern:
Activation of the coolant shutoff valve on the Tiptronic transmission:
> Check Engine warning light activated in instrument cluster,
> Diagnostic trouble code P2181 and/or P3081 in the DME fault memory.
Information:
Pinched vacuum lines, or ones not pushed on for the coolant shutoff valve and disc valve on the Tiptronic transmission, can lead to the disc valve controlled by the vacuum from the coolant shutoff valve not being closed, and thus lead to the complete cooling system (engine and transmission cooling) being opened during the warm-up phase of the engine.
This can lead to an extended warm-up phase of the engine which is detected by the DME control module. In the instrument cluster, the Check Engine light is activated, and the following diagnostic trouble codes are stored in the fault memory of the DME control module:
> P3081 - Engine coolant temperature implausible
> P2181-Thermostat stuck open
If this fault type occurs, first the operation of the coolant shutoff valve and the disc valve on the Tiptronic transmission need to be checked with the PIWIS Tester. If their function can not be confirmed, the vacuum lines for the coolant shutoff valve and the disc valve on the Tiptronic transmission must be checked for correct seating on the various valves, clamping points, and for damage.
In order to prevent pinching of the vacuum line for the coolant shutoff valve, an additional length of line as well as an additional protective tube has been installed between changeover valve and Y-piece of the vacuum line, in the area of the generator and the intake system on the engine, on engines produced from the date of introduction listed below.
Introduction
Parts Information
Tools:
PIWIS Tester P 9718
Work Procedure:
1. Raise the vehicle at the jacking points provided on a platform lift, see Workshop Manual "401000 Raising the vehicle".
2. To be able to view the disc valve on the Tiptronic transmission, remove the rear underbody cover, see Workshop Manual "519419 Removing and installing rear cover".
3. Lower the vehicle.
4. Connect PIWIS Tester to the vehicle and switch on.
5. Connect exhaust extraction system to the vehicle and switch on.
6. Switch the ignition on and start the engine.
7. Raise vehicle again, and have a second person operate the PIWIS Tester.
8. Observe the position of the actuating lever (see - Figure 1, Item A) on the disc valve. Figure 1 shows the actuating lever in position 0 (disc valve opened.
Note!
When there is a vacuum present, and proper function of the coolant shutoff and disc valve, and when the engine is running and the coolant temperature is less then 185 F. (85°C.), the disc valve is closed, i.e. the actuating lever of the disc valve is in position 1.
9. Using the PIWIS Tester, select the Tiptronic control unit in the "Control unit" menu and select the menu item "Drive links" in the Tiptronic function selection.
10. Using the PIWIS Tester, reset the coolant shutoff valve and then reactivate it. Start and stop the resetting and activating of the valve using "F8". While doing so, observe if the disc valve is opened (see Figure 1, Item 0) and then closed again (Figure 1, Item 1).
11. After the check with the PIWIS Tester is finished, lower the vehicle and switch off the engine and ignition.
Warning!
Burns caused by touching hot engine parts.
> Parts of the engine can be extremely hot.
> Wear protective equipment if necessary.
12. If the disc valve should always be open (see Figure 1, Item 0), check if the vacuum lines for the coolant shutoff valve and disc valve on the Tiptronic transmission;
> are tight on the connections of the various valves (change-over valve in the area of the generator, coolant shutoff valve and disc valve on the Tiptronic transmission or
> if the vacuum line for the coolant shutoff valve is pinched between generator and intake system on the engine or
> if the vacuum lines show any sign of damage.
13. If necessary, push on any nonconnected vacuum lines onto the connections, and replace damaged vacuum lines.
14. If the vacuum line for the coolant shutoff valve (see Figure 2, Item 1) is pinched between the generator and intake system on the engine, or has been installed under tension, an additional length of line as well as an additional protective tube is to be installed between the Y-piece of the vacuum line (see Figure 2, Item 2) and the change-over valve (Figure 2, item 3), > Continue with Step 15.
15. Pull off Y-piece of vacuum line (see Figure 2, Item 2) from the change-over valve (Figure 2, Item 3).
16. Cut off a 35 mm piece (see Figure 3, Item 3) of the vacuum line, part number, 000.043.205.01.
17. Push on protective tube, part number, 928.574.717.03 (see Figure 3, Item 4) up to the stop on the change-over valve (Figure 3 Item 2).
Note!
To avoid malfunctions, insert vacuum line approx. 10 mm deep in the protective tube or in the Y-piece during assembly. Only use water as a sliding compound, if it is needed.
18. Insert the first end of the 35 mm long vacuum line (See Figure 3, Item 3) approx. 10 mm deep in the protective tube (Figure 3, Item 4).
19. Push on the Y-piece (see Figure 3, Item 1) approx. 10 mm on the second end of the vacuum line (Figure 3, Item 3).
20. Switch the ignition on and start the engine.
21. Raise the vehicle again and test the function of the coolant shutoff valve and the disc valve on the Tiptronic transmission with the PIWIS Tester as is described in work Steps 9 and 10.
22. Lower vehicle, and switch off engine and ignition.
23. Switch off and take off the exhaust extraction system.
24. Switch off and disconnect the PIWIS Tester.
25. Raise the vehicle again and install the rear underbody cover.
26. Lower the vehicle and remove from the platform lift.
Working Time
Damage Code: 3867 16 000
References
Disclaimer