8007 CDR23: Diagnosis/troubleshooting

DIAGNOSIS/TROUBLESHOOTING (8007 CDR23)

Work instruction			Display OK	If not OK
1	Read out CDR23 fault memory	Connect and start the Porsche System Tester II 9588 and switch on the ignition. Select 911 (996) in the Vehicle type menu and confirm with the "FORWORD" key. Select CDR23 in the Control units menu and confirm with the "FORWORD" key. Select Fault memory in the 911 (996) CDR23 function selection and confirm with the "FORWORD" key. Read out fault memory. Clear fault memory. Remove ignition key and switch on ignition again Read out fault memory. Extract ambient data, press the "FORWORD" key	The fault is remedied -> End	Fault code is still displayed Step 2
2	Check MOST components	In the Control units menu, select CDR23 Select MOST component check in the 911 (996) CDR23 function selection and confirm with the "FORWORD" key. Wait for the end of the automatic check The duration of the check depends on the number of existing MOST control modules Press the "FORWORD" key	CDR23 > amplifier optically OK electrically OK Amplifier > CD changer optically OK electrically OK CD changer > CDR23 optically OK electrically OK	An optical fault is displayed 3 An electrical fault is displayed 4
3	Optical fault	Replace the relevant optical waveguide between the listed faulty components with the optical waveguide test line 9712 that is provided as a special tool. Check MOST components again.	Replace the faulty optical waveguide with the relevant spare part -> END	Replace the relevant recipient MOST control module STEP 2
4	Check diagnosis ring line for open circuit	Check diagnosis ring line between the listed faulty components for an open circuit Switch ignition off Disconnect the plug connections of the existing MOST control modules Measure the resistance of the diagnosis ring line between the relevant plug connections	< 0.5 STEP 5	Remove open circuit in diagnosis ring line -> END
5	Check diagnosis ring line for short circuit to ground	Check diagnosis ring line between the listed faulty components for short circuit to ground Switch ignition off Disconnect the plug connections of the existing MOST control modules Measure the resistance of the diagnosis ring line to ground	STEP 6	Remove short circuit to ground in diagnosis ring line -> END
6	Check diagnosis ring line for short circuit to B+	Check diagnosis ring line between the listed faulty components for short circuit to B+ Switch ignition off Disconnect the plug connections of the existing MOST control modules Measure the voltage of the diagnosis ring line to ground Switch ignition on	0 V STEP 7	Remove short circuit to B+ in diagnosis ring line -> END
7	Replace PCM2		-> End