General
General
This manual is intended for trained automotive workshop personnel who have successfully completed Porsche training seminars on the respective systems and who possess the necessary theoretical and practical knowledge to perform work on complex systems.
The basic prerequisite for all work on the DME is the acknowledgement and observance of safety regulations and warnings.
NOTE: The following diagnosis and troubleshooting procedures are oriented toward and described for left-hand drive vehicles. Plugs and jacks specified may have different pin assignments for right-hand drive vehicles, which could lead to both misinterpretation during troubleshooting and to unpredictable accidents. Therefore, work should not be performed on right-hand drive vehicles without the correct circuit diagram or diagnosis and troubleshooting descriptions for right-hand drive vehicles.
This OBD II manual DME 7.1.1 covers the following vehicles:
- Cayenne with V8 turbo engine, as of model year 2003
- Cayenne with V8 naturally-aspirated engine, as of model year 2003
- Cayenne with V6 naturally-aspirated engine, as of model year 2004
This manual describes the diagnosis and troubleshooting procedures for the engine control module DME 7.1.1. It is based on the OBD II versions (USA version, OBD = On-Board Diagnosis). This includes the EOBD (European OBD) and RoW (Rest of the World) versions that were adapted to the respective national laws or regulations regarding diagnosis.
The main differences between the OBD II and EOBD versions include the fuel tank leakage test required by law in the USA and the criteria for storing faults and activating the CHECK ENGINE light (abbreviated CE below), which is also referred to as the MIL (Malfunction Indicator Light).
The following functions are assured by the OBD II system:
- Detection of combustion misfiring
- Monitoring the Efficiency of the Catalytic Converter
- Monitoring the fuel tank ventilation system
- Monitoring the fuel tank system for leaks
- Monitoring secondary air injection.
- Monitoring the adaptation limits (e.g. of oxygen sensing, boost pressure control)
- Monitoring the oxygen sensors
- Monitoring the thermostat and water temperature sensor
- Monitoring positive crankcase ventilation (via lambda adaption).
- Monitoring the transmission (Tiptronic control module)
- Monitoring emission-relevant sensors and actuators associated with the DME (previous scope of OBD 1)
- Triggering the Check Engine light and storing faults in the memory
- Indication of monitoring readiness.
- Output of existing diagnostic trouble codes (DTCs)
- Storage of defined operating parameters in the event of a fault (including freeze frame)
- Functional checks of the OBD system (warm-up cycle, driving cycle)
- Communication with standardized control-module tester (scan tool) in the prescribed modes
- Standardized read-out of operating data such as rpm, temperature, etc.
Digital engine control module DME 7.1.1
Location of DME control module
DME 7.1.1 is a proven, highly reliable engine control module, which was specially adapted to suit Porsche requirements. It is located under a cover in the right-hand part of the plenum chamber (engine compartment) and is protected against penetrating moisture.
Unlike with the DME control modules Porsche used previously, the fault memory is retained even after the battery is disconnected. It is especially important to bear this fact in mind when installing control modules as a test and then returning them to storage or installing them somewhere else. In cases such as this, the fault memory must be erased again before removing the control module.
When the voltage supply is interrupted, the following control module values will be deleted:
- All adaption values
- Learned values of the throttle adjusting unit
- Ready statuses of the individual diagnosis routines.
- Freeze frames (ambient conditions; see following chapter) stored with the faults
Bear in mind that programming the DME (e.g. loading a new data record) will also delete the values mentioned above.
Note on adaption
The DME control module must perform a learning and adaptation routine for the throttle valve adjuster if:
- the power supply to the DME control module was interrupted.
- the DME control module connectors were unplugged.
- a new DME control module was installed.
- the throttle valve adjuster was replaced.
- the DME was programmed.
To initiate adaption:
1. Switch on the ignition without starting the engine
2. Perform a "throttle adaptation" under the "System adaptation" column using the 9588 Porsche System Tester II.
The following conditions must be met, otherwise adaptation is not possible:
- Do not press the accelerator (make sure there is no carpet pressing on the accelerator, for example)
- Stationary vehicle
- Battery positive voltage between 10 V and 16 V
- Engine temperature between 5 °C and 100 °C
- Intake air temperature > 10 °C
Standardized fault codes according to ISO 15031
Diagnostic trouble codes that can be issued by the control module are standardized according to ISO 15031. This ISO standard is based on SAE J 2012.
The fault code or DTC is always a 5-character alphanumeric value, e.g. "P0100".
The first character (letter) of the code identifies the system which has set the code. A total of four system types are covered:
- P for powertrain (this is the first character of all OBD II fault codes)
- C for chassis
- B for body
- U for future systems
The P codes are classified in 2 main categories according to ISO 15031:
- Uniformly standardized codes: P0XXX and P2XXX; these codes are identical for all manufacturers
- Manufacturer codes: P1XXX and P3XXX: only the first 3 characters are standardized here (example: P13XX for ignition-system diagnosis or misfire detection); the last two characters are freely selectable by the manufacturer.
Only the P codes are required for OBD II.
The standardized codes are subdivided as follows:
P0001 to P0299 Fuel and air metering
P03xx Ignition system and misfire detection
P04xx Additional emission control systems
P05xx Speed and idle air control
P06xx Computer and output signals
P0700 to P0999 Transmission
P2000 to P2299 Fuel and air metering
P23XX Ignition system and misfire detection
P24XX Additional emission control systems
P25XX Additional input signals
P26XX Computer and output signals
P27XX Transmission
P28XX Reserved
P29XX Fuel and air metering