Diagnostic Conditions

Diagnostic Conditions

NOTE:
- Important. All unnecessary electrical loads must be switched off before the diagnosis. When working on the vehicle with the ignition switched on for fairly long periods (above approx. 15 minutes), a suitable battery charging unit must be connected.
- The control module can only detect the fault if the requirements listed under 'Diagnostic conditions' are met. For this reason, the specified procedure must be observed after a fault is repaired:
1. Clear the fault memory after printing out or saving.
2. Satisfy the requirements listed under 'Diagnostic conditions' or perform a short test with the 9588 Porsche System Tester II. It should be noted here that, owing to reset adaptation values (in particular for fuel supply and misfire detection), fault detection by the DME control module is only possible after a fairly long driving time. If may be necessary to observe the relevant adaptation values ("actual values") during a subsequent test drive to be able to identify any trend
3. Read out fault memory again.

Possible causes of fault

NOTE: The 'possible causes of fault' that are responsible for the fault are listed here. Please note that in certain circumstances further faults may be stored in the fault memory after troubleshooting (e.g. if plugs are disconnected). After repairs, read out the fault memory of all control units and delete the faults appearing as a result of the troubleshooting and repairs.

DME faults

NOTE:
- A faulty control module is extremely rare. Although in theory almost any fault can also be caused by a faulty control module, it has been shown in the past that, particularly in the case of DME control modules, even control modules sent in for checking were OK.
- At this point we again stress that before exchanging a DME control module (the final logical step at the end of unsuccessful troubleshooting), all other possible fault causes must be rigorously checked; if necessary, delete the fault entry and perform a test drive or short test.
- If other faults are entered, then remedy these first as instructed (An example: a fault in adjusting the inlet camshaft may under certain circumstances also lead to an oxygen sensor fault being output).
- Fault entries solely in connection with the troubleshooting, repair or programming of control units (e.g. CAN timeout faults) should be deleted.

Diagnosis/troubleshooting

NOTE: The fault memory Info key [F8] on 9588 Porsche System Tester II can be used to access the 'extended fault memory'. Besides the freeze frames and environmental conditions, this also includes information on the fault type.

Fault type
The following fault types are possible for the DME
- Above upper limit (Max)
- Below lower limit (Min)
- No signal/no communication (Sig)
- Signal implausible (Plaus)

Several fault types may be stored at the same time.

Fault status
The following status types are possible:
- present
- not present

This information should be saved using the Save key [F4] and printed out.

NOTE:
- Faults "not present": Where faults are entered but not actually present, after obtaining or adjusting the diagnostic conditions, wiring positions connected to moving parts on and in the vehicle must be checked systematically. Various statuses that can cause a fault to occur must be simulated with the aid of the wiring diagram. It should be noted that the 9588 Porsche System Tester II shows the current fault status only conditionally. The fault frequency counter gives information on operating time and mileage at last fault occurrence
- In difficult cases where faults are currently not present, it is recommended to clear the fault memory (after printing out) and to observe whether the fault is re-entered whilst simulating a loose contact.
- Visual inspection of plug connections: As part of troubleshooting, it must be ensured that the pins of affected plug connections, both on the wiring side and component side, are neither damaged nor corroded. Furthermore, the wiring and plugs must be checked for external damage (cracks, etc.) and proper contact (pins not bent, spread or pushed into the housing). Repair damaged or corroded pins if possible, otherwise replace them. Repair or replace damaged wires. If wiring to the oxygen sensors is damaged, always replace the complete sensor.
- Visual inspection of components: As part of troubleshooting, it must be ensured that there are no signs of visible damage (e.g. cracks, deformation or chafed areas) on the affected components and wiring harnesses. This is particularly important for components that cannot be tested with a multimeter, e.g. bar ignition modules, or components that can cause sporadic faults due to penetrating moisture.
- Battery voltage and signals: A battery voltage of between 11.4 and 14.5 V is generally required for diagnosis/troubleshooting. This must be checked and, if necessary, guaranteed by means of a battery charging unit.
- Specified resistance values are based on an ambient temperature of 20°C unless otherwise stated.

End of troubleshooting (-> End)
-> End marks the end of the described diagnosis/troubleshooting in the troubleshooting tables. After successful repair, the fault memory of the DME control module must be cleared and, if necessary, adaptation of the throttle adjustment unit performed, followed by a short test or test drive to achieve the diagnostic conditions for the particular fault. Afterwards the fault memory must be read out again. Depending on the country, Ready statuses must be generated.